The information about the stick magazines is partly true. At first, Auto-Ordnance made semi-auto Thompsons that used the normal SMG stick and drum magazines. Then they changed the design in the magazine area and went to new stick mags and a new drum that holds 40 rounds; neither will fit the older guns or the original TSMG. Now, the new drums and sticks are 10 round and the rest is for show. The new guns will not accept original SMG stick mags without modification and will not accept original SMG drum mags at all - trying to make them fit will destroy them.
Original 50 round drums were going for around $400+, 100 round drums for well over $1000. So I don't think you want to get out the grinder to try and make these work in your semi-auto.