If you can do 3 sets of 12-15 of any given exercise, you're in the right range. There's no need to be going to the point of failure if you're not looking to gain muscle, so in a sense, yes that's man talk for muscle building.

Just make sure it's not too easy or it's not helping, but it seems like you're doing it just right.
One thing I might recommend is to focus less on arm exercises and focus more on chest and back exercises. The bigger muscle groups will give you better results and keep you from putting any more size on your arms if that's an issue for you. Chest and back still hits the arms, so it's not like they're being neglected.