Hello ,
Center shaft and center hole are similar .
On 117 , spool edges diameter is smaller than on 120 (and nearly smaller than on 620) .
I have some with wooden center shaft for non-modified Original Rolleiflex TLR (1929-1932) : it takes only six pictures 6x6 .
120 can't be used with these old Rollei : spool edges diameter is too big . It's possible with 620 while reducing internal winding key ; a lot of Original Rolleiflex were modified for that .
Edit : see
here , on this french website : on the second picture , from left to right : 117 , 620 , 120 .