I got two g1 megatrons, one is prerub(stamped Takara only, no date). It's in near mint condition, however, the legs are not tight(It's not really loose, but when you pull the legs out it feels very smooth and doesn't really lock into anything)

The other one is stamped "takara 1974, 1983". It's at most c7 condition, however the joints are very good on this one, the legs are very tight when trying to pull it, and they firmly lock into place.

Since the prerub one is near mint, it would make more sense for it to have tighter joints, but it doesn't. Was there a mold change for g1 megatrons?

 

i got the megs with the 1974, 1983 stamps and it is a bit worn and weathered, the joints are in good shape, too.
i wish his box i bought with him was C-8...or at least as well aged as the toy. it looks like a negative C-2.

 

There are minor veriations in the casting of toys that can make joints loose on one cast and tight on the next.