Wouldn't you know that it would turn out that Jan 1967 appears to be the change over period for the earlier cast to later stamped upper hinge.
Off subject slightly but adds to the muddy waters on hinges:
The STAMPED version looks to be used or at very least, had been used at times prior to the January date...I doubt that I have the ONLY example of this.
I believe one or more of the aforementioned threads should cover what I found on my example (11/02/66 actual build date).
My example had BOTH uppers stamped type and it was evidenced to me with the factory sealant on the upper hinge mounting (still bonded to the LH door post at time of restoration). Further evidenced, though I had repainted the car, including the hinge area...but yes, the factory paint was still on even the sealant of both my LH hinges when I stripped the hinges during restoration. Also reported in another thread, my RH door AND their door hinges were both changed BY ME back in 1978 because I bought the car wrecked and I specifically remember noticing the cast style hinges (both upper & lower) on the replacement door at the time. At the 1978 time of repairing the wrecked car, I figured the RH stamped one might be bent, I felt it wise to use both hinges that came with the RH door (and fender). Dates stamped in the fender and door make them both dated mid-December. I assume the donor car was a mid to late December1966 SJ example (going by the under-side painting details of the fender. Note: Donor parts car was an original paint car.
Now, in 1978, I cared ONLY about getting the car drivable...what 16-year old wouldn't so details like "correct hinges" would have been unimportant to me back then. Nontheless, I have no doubts in my memory about the upper hinge diffences. REMINDER: I also have on hand a full set of hinges from another pair of December San Jose S-coded Coupe doors that BOTH had the stamped uppers and CAST lowers. Clearly there are two examples like I describe and the spare doors ALSO are in ORIGINAL PAINT.
It would have been very easy, pretty much cost-free even, to have simply installed all Cast Hinges during my restoration and have complied to what is commonly known (as well as what MCA rules suggest)...
...I have TWO original paint examples in this Pre-January 1967 detail and I am 100% sure, my doors on hand were originally equipped with the stamped uppers. This is why I chose to return my RH door to the stamped upper (and lower cast).
Now, off my soapbox and back to the O.P.'s concerns.
On last edit: facts straightened out on my examples on hand after reviewing previous threads and my own pictutes.