You can charge whatever you like ofcourse.
As for modeling and making textures and weapons, been there, done it, my goodness even create games (not FPSC though, including lot's of weapons, characters, items, textures, coding, huds). Have create a good number of FPSC items already (models, segments and even a weapon), so I know how much time it takes and because of that I really think it's overpriced.
But 2 people, 2 opinions and I'm sure some will buy, but if you'd have more FPSC market conform prices, I'm sure lot's more people would buy