No, it would depend on what branch of the military they serve and for how long, how much combat experience they had and how much time they have spent using small arms. Your average Marine probably has around 40-50 skill in guns I would say. A Green Beret probably has around 75 to 85 skill in guns depending on rank and experience. The only people who could say they have 100 in guns would be the people who were born and raised around small arms and have experienced it using them and mastering their shooting on a daily basis, even then it would be questionable because part of having a high gun skill in fallout means you have experience using a large variety of weapons.
Anyone in the Army, I'd think would have a higher Small Guns score, given that they out shoot the Marines every year at the Nation Matches in Ohio, but they'd have lower Repair and Survival scores, since they see much less action. Anyone in the Airforce would have low Small Guns but higher Repair and Science, since most of the Airforce isn't flying but technical and logistical work. The Navy is up for grabs; I guess it would look a lot like the Airforce but with lower Small Guns. As far as the Marines go, yeah, they'd have average 50-60 Small Guns, but they'd also probably have decent Big Guns and Survival scores too, with a 75- score in Repair, given that they aren't given %$@& when it comes to good equipment, and they have to jury rig and make due with what they have.
Green Berets would have excellent Small Guns, Speech, Sneak, and Repair.
Army Rangers would have excellent Small Guns, Sneak, Survival, and Unarmed.
Navy Seals would have excellent Small Guns, Sneak, Explosives, and Melee Weapons.