44 years ago when I was stationed on my first military base there were few firearms carried in the course of the day. If you were permanent party soldier you could have a pistol or long gun in base housing, and the same is true today. You didn’t carry personal weapons in uniform but you get use them off duty to hunt and for protection in your residence or in the wild.
The only firearms carried were paymasters and the like and the occasional armorer issuing weapons for training.
Perhaps there is more registering of who has what weapon on a base now, but since there is less payment in cash at monthly pay tables, the side armed soldier was rare then and rare now. Weapons are a tool not jewelry. When there is no work for the tool, you don’t draw it or carry it in the workplace as a matter of course on a fairly secure military base. Planes and special gear get a certain amount of guard duty type protecting, then and now. MPs and other forces of a similar nature are armed.
The civilian and fort police are mainly guarding gates since 9/11. The military police are who roam the posts, and they are armed.
Military forts have never been an open carry area in the last three generations that I am aware of. If you work in a large factory you don’t carry on a work floor except the occasional guy who in a deep concealment fellow and who knows the count on that?
Did those policies work to prevent the two mass murders at Fort Hood?