Jake,
The thing about the original 212 and the 215 is that they were of different lengths.
The original #212 was considerably shorter and was renumbered #215 when sent to Mexico.
That was when and why the change was done.
What gets weird for modelers is that the folio sheets were never updated, so the folio on #212 is incorrect for the longer #215/212. All of the old Labelle kits were made from the short folio.
If your #212/215 is the same length as a coach, you are ok. If you have a short combine, it's OK for the original #212, not the one that we all know as #212.
I agree it would have been green before Gold.
Mike