I think the are the same. (but wait for a response from a expert on the old mac's)
I have 1-40's, 1-50's but I don't have a 250 but I have used some 250 stuff on my 40's and 50's such as mufflers, carbs, bars and I think I have interchanged some of the handles.
Some of the 250 mufflers exhaust can be aimed different directions.
I like the old cast metal one piece mufflers sound and they also allow for easily priming through the muffler holes for a cold start prime.