Sort of, the nose cone / mounting housing is different. You can switch those and make it work. I've done it.
Its a little bigger I remember the 1st time I changed the starter out of my 250 mav, the parts store, gave me a cheap rebuilt one. When I took it home to compare, I noticed it was slicghly shorter, and then also noticed on paper inside the box it was for the 170 motor. So I took it back, and had them special order me the right one. I think it only cost me $35, the other one was only $21(This was back in 1998)