ok , I've got pics of the "early" electric motor,
front and
back - this is the only style OEM wiper I've seen, and the repro from the vendors for 55-7 has the same configuration, but different motor and drive [made by Newport Engineering, excellent replacement] - the one said to be for 58/9 has a slightly different mounting arrangement, but the drive looks the same
I couldn't find the transmission arms right off, hafta dig deeper into boxes, but I'll get to that - the 5-7 arms do have a "kink" and there is a definite right and left, but I guess they changed some - will be interesting to see how
so if you're looking for originals to replace vacuum units, this is what you want .... and I'll be hoping for some pictures from Patchy of the other unit
Bill