Hi
I am glad you are happy with your situation but these two threads are not the same. BSW has a thread angle of 55 degrees while the UNC has a thread angle of 60 deg. OK, you can get away with interchanging if you are only using parts which are under too much stress, but, your head may shake loose if you walk with your camera attached in the field. That could be very expensive, it happened to me. The tapping drills for these threads show how different they are, full details are on this site:
http://www.britishfasteners.com/threads/unc.html
Take care.