There was a recent thread that mentioned that there were two different top shells for the 1050 floppy drive.  As it happens, I just came across a box with an 800 & two 1050s.  They were pretty dirty, so I disassembled everything to clean them.  The two 1050s had different top cases, so I thought that I would take some pics of the differences and post them here.      Here you can see that the front edge has different interlocks that go to the front frame.  You can also se