Charles you asked this question at the right time. I pulled my front end to do some clean up and other stuff during Covid and getting ready to put it all back together.
1. My drivers side housing and extension are known OEM originals. Besides part numbers, they both have numbers in ovals shown in pictures which none of the passenger side parts have. OEM housing is cast with C5ZB-13A045-A, SAE N 64 CR, FoMoCo in oval, 65159 LH and individual numbers 1-12 each in an oval. The extension is C4ZB-13064-A, 64115 (can't make out the rest), FoMoCo in oval and 5 what appear to be cast in support spots. The extension also measures 3/32 thick at green line in picture.
2. My car came without crush triangles on the driver fender. I replaced it in the early 80's with a used fender that has triangles. The drivers side fit is perfect. I don't know if it's an OEM or a NOS fender, it doesn't have a date code up where it bolts to the inner fender but does have one on the inner support. Unfortunately I can't make out the number. Any idea why it would have a stamp there?
3. My passenger fender is a NOS fender I bought from Ford in '83 and it doesn't have anything stamped on the inner support or anywhere.
4. I know the passenger housing and extension are not original to the car so take this for what it's worth. The housing is cast with 64136 RH, C4ZB-13100-G, SAE H 64 CH and FoMoCo in an oval. There was an extension on it that I could never adjust to fit, it was cast with C4ZB-13052-C, 64114-151 and FoMoCo in a rectangle. It also has no cast in support dots and measures 1/16" thick. I replaced it with a C4ZB-13052-A, 64114-151, 6 cast in support spots and FoMoCo in an oval and 3/32" thick and that fits perfectly. I tried to trace the outline of each, the pink line (bad extension) deviates a little but the dimensions on these require you to roll them as you trace the edge to keep the edge down so it's a best effort trace. One other thing, from the outer most edge to the inner circle around the bulb, the bad extension was 1/16" less than the good one. I think the hole extension may have been off center because it was impossible to match the gap between the fender and hood...it was always too tight.
5. Years ago I picked up a NOS drivers housing because my original had cracked in the normal place. I just painted it a few weeks ago to go on the car but now I'm wondering how it will fit. I'll update that later. Part number is C5ZB-13A045-B, SAE H 64 CR so I'm sure something will be different.
Hope this gets you started
Steve-