The 2 oz. over factory spec is to limit people from getting crazy with tungsten guide rods or hiding wight inside the gun. Lighten your trigger, tune the internals for "enhanced reliability", change the sights, and add grip tape on grip if you want. basically that's all you can do to a production gun. There is no box for USPSA, but there is for IPSC. At the larger area match, they don't really tear down your equipment and break out the weight scale, just just make sure your holster and mag pouches are in the correct position. I have never cracked a glock base pad and they are so cheap that I just buy extra base pads if they get so scratched up beyond useable function. I see no need to spend more money and glue on a rubber base pad.
If your haven't done anything to your gun and want to shoot production, you would be safe to come out and shoot with no worries, just load 10 rounds in your mag and shoot.