I am kind of new to this and I just made tier 1 on the new task force Omega rep. I want to chose weapon proficiency but my toons weapon proficiency is all ready at 100%. Does the +30 weapons prof stack with the 100% I already have?
Yep. It's not really 100%, it's 100 points (well, 99), and you can go over. I tend to run some of my science skills at levels above 200 points through various consoles/skills/mods, as the bonus conferred does generally increase beyond 100.