Samantha notices that Lt. Col. Carver's service pistol is "missing." Officers outside of combat zones aren't issued service weapons.
It's impossible for an Army officer, especially a decorated West Point graduate with Vietnam combat experience, to spend 34 years in the Army and retire as a Lieutenant Colonel (O-5). Either he would have made general-grade rank (O-7 and above) by about the 20-year mark, or he would have long since been forced out as unpromotable.
Carver's comments that she is not used to seeing him out of uniform. That's possible only if she never saw him except at his office. Military personnel don't wear uniforms off duty.
If Bull Carver is retiring in 2003 after 34 years of service beginning with entering West Point at age 19, he couldn't possibly have served in Vietnam. He would have been commissioned in 1973 months after U.S. involvement in Vietnam ended.