not everyone is a gun dork, and i for one get really annoyed when i join a deathmatch and have to pick my gun, only to see what appears to me as complete gibberish (ex L85A2). i usually like to know whether it's an assault rifle, sniper or what. maybe in call of duty or another gun-centered game it's acceptable, but the average player in a lego game is not going to know the official name of a gun. some guns, like the ak47 or m16, are common enough to pass by most people.
more on topic, the gun looks nice. i think that some pieces, like the trigger guard (?) and the iron sights are too thin to fit blockland, and the body of the gun looks a bit too square (corners too sharp for my liking). it doesn't really have the modern day gun look, but more on a retro-blockland appearance- although it wasn't what you appear to have been aiming for, that's not necessarily a bad thing.