Congratulations on what sounds like a really nice bike, very similar to mine. Yes the fixed cup comes out. On mine I believe it was French threaded, right hand thread. I assume that yours has the original Stronglight bottom bracket. According to my second edition Sutherland's manual a French threaded fixed cup will have one ring cast into the face and 8 sides. A Swiss cup will have no rings and eight sides.

Please post a photo when you can. You will be able to post photos when you have 10 posts. This is an anti-spam measure.
Brent