the differences internally are more with the 5cm one...some of the groups have linings that remind me more of rangefinder Nikkors
i am now looking for a 10.5cm tm to take apart, i did not document mine
the 10.5cm tm has the most slop in my experience, even propagating to the non-tm versions. many corrected holes, etc. you could see that some people were putting holes where there should not be and then covering them with tin solder, etc. there are also signs of extensive trimming which were corrected with brass inlays, too. it gave me the impression that Nikon was in a hurry to finish these. i read from somewhere that 10.5cm assembly line was understaffed so this is probably the result. not sure if i read it from the 1001 articles or i heard this from a Nikon employee but this is something that is confirmed. maybe i heard this from the Nikon F anniversary talk, i forgot.
i offered my 10.5cm tm to be displayed at the Nikon Museum but they declined citing that they will be very afraid if something happened to my lens.
