If you have one of them you could try taking it to a parts supplier and they may be able to match it visually if you get an experienced friendly counter person.

Only other thing I can think of is a jiggery pokery.
Get the slightly smaller legs, put a washer and a nut on them, use this to adjust the level and then use another washer and nut on the top to lock them in place.

Could also get a larger set and have the shafts machined down to the proper size but this could be a pain trying to match the size and thread type.

Hopefully someone else will have a better solution.