Wendy Goodwin and the folks at Cape Cod shipbuilding have a lot of the original HMC casting molds for the 12 1/2.
I just purchased a set of gudgeons and pintels for my 12 1/2 from them and they are the same size as my old worn out ones, meaning they were not re-castings. The quality was very good in that they fit together well with no slop.
Some other vendors (I won't mention names, are re-casting parts from the original 12 1/2s, which end up being smaller due to the shrinkage.
You must specify that they are for an original wooden boat, or they might give you what they redesigned for the bulleyes