Yes, it means that it is the fourth model of the 12" 3/8" bed lathes. That it has Timken bearings instead of babbit. And that it has power cross feed. All of the 740x models had Timkens. All of the 738x models had babbit bearings. All 14 of the 3/8" bed Craftsman 12" lathes had the same countershaft, so that isn't an issue. The only thing that the model # does NOT specify is the bed length except for the last two number for those lathes, 101.27430 and 101.27440. For that, with the first 12 you have to also have the catalog number. But you are correct in that the Sears model numbers are just arbitrary. The numbers themselves do not mean anything. You just have to know what the complete number means.
Atlas was almost alone among lathe manufacturers in having meaningful part numbers or partially meaningful model numbers. And that was only for the 10F Series lathes. The earlier 10's were either 10, 10A, 10B, 10C, 10D and 10E and within those you had to specify 1036. 1042. 1048 or 1054. Clausing and Logan had none that I know of. South Bend almost had none. Most other manufacturers had none.
But to answer your original question, no, not really.
