Two men told a newspaper they were told to expect Mr. Bush, but never saw him. But a third veteran said the president, then a young officer, did fulfill his duties.
Yet another former Guardsman claims Bush aides destroyed military records to protect Mr. Bush, which the White House and the aide allegedly involved denied.
The claims and counterclaims fueled another day of debate over the president's service record.
Questions over the president's time in the military first surfaced in 2000, but reemerged this month when Democratic National Committee chairman Terry McAuliffe accused the president of being absent without leave from his duties.
The White House, which insists Mr. Bush fulfilled his duties, has released two sets of the president's military files this week to try to rebut Democratic claims that the president neglected his duty during 1972, when he transferred from the Texas Air National Guard to a unit in Alabama to work on a Senate campaign there.
On Tuesday, the White House released retirement and pay records showing days for which the president was paid in 1972 and 1973.
But the records did not indicate where the president served, what he did or where he was during several months where no service was recorded.
On Wednesday, the White House released the record of a dental examination in January 1973 at an Alabama base.
But the dentist who treated Mr. Bush has no specific recollection of seeing the future president, saying that at that time he would have been "just another pilot." The timing of the exam did not clear up questions about what Mr. Bush did during gaps in his record in 1972, and it was unclear why Mr. Bush was examined in Alabama two months after the campaign on which he was working ended.
The records have also raised questions unrelated to the president's service. To fight a story that arrest records on young Mr. Bush's record were blacked out, the White House revealed they included an arrest for a student prank at Yale, two speeding tickets and two traffic accidents.
"I'm just amazed by the kinds of conspiracy theories that some have chosen to pursue," said Scott McClellan, the White House spokesman.
CBS News Correspondent Bill Plante reports the White House backed off its pledge this weekend to release all the president's records. Aside from the dental record, they did not release other medical records that were recently received from the Air Force.
Now veterans of the Guard are adding their claims to the documentary record.
In a six-year old letter to Texas lawmakers obtained by CBS News and in a new book, former guard officer Bill Burkett claims that in 1997, Texas Guard commanders purged Mr. Bush's records to "make sure nothing will embarrass the Governor during his re-election campaign, or if he runs for president."
"I was troubled sufficiently within my own conscience that there was an effort here to cast an image that was better maybe than the individual's record," Burkett said. He claims he overheard a phone conversation in which Mr. Bush's then chief-of-staff Joe Allbaugh gave the order to scrub the records, and later found some in the trash.
The White House dismissed the claims, saying Burkett has no evidence to back them up. Allbaugh called the story "hogwash."
"This guy doesn't know what he's talking about. I don't know who he is, what he heard, or what he thought he heard," Allbaugh said. "Hearsay, as far as I'm concerned. I never said what he said."
Separately, two Guardsmen at the Alabama base to which 1st Lt. George W. Bush was told to report told a Memphis newspaper they never saw him either, despite the fact the base was all abuzz about a politically-connected guardsman coming in.
"I remember that I heard someone was coming to drill with us from Texas. And it was implied that it was somebody with political influence. I was a young bachelor then. I was looking for somebody to prowl around with," Bob Mintz, now 63, told The Memphis Flyer.
"I never saw hide nor hair of Mr. Bush," said Paul Bishop, a Gulf War veteran who voted for Mr. Bush in 2000.
But Bill Calhoun says he was stationed at the Alabama air base, and says Mr. Bush was there when he was supposed to be, while he was in Alabama working on a Senate campaign.
Other Guard officers have noted that Mr. Bush may not have been noticed among the hundreds of men on the Alabama base. But Mintz said the flying squadron to which Mr. Bush was supposed to have reported numbered around 30 men.
Mr. Bush joined the Guard in May 1968, and there is no question about his service in his first three years. However, critics have questioned how Mr. Bush leapt a head of a long waiting list to get into the Guard, whose members rarely went to Vietnam, and how he rose quickly to become and officer and a pilot despite relatively low test scores.