Thank you for your reply. When I look at pictures of the video camera online, I see others have a square one that says "Leica Dicomar" on it (that I have). Is the one I have on there now not interchangeable with this one?
The bit that says Leica Dicomar is a lens hood or shade. It is a metal (or maybe plastic) piece that acts like the brim of a baseball hat. It is not a lens. The square metal piece on the front of the lens does come off if you need to clean under it: http://www.adamwilt.com/24p/index.html#Cleaning_the_lens