1970 914/6 Transmission & CoA, Stampings Options

[John_914]

I've have a 70 916/6 restored to at or near concours condition about 20 years ago. I've owned the car for 14 years. All numbers/paint match, but the CoA does not list the 5-speed transmission number, says "information not available."

The transmission has correct tail shifter and all linkage per 70 916/6. However, the transmission is stamped with 914/4 number. As part of the resto, the trans was completely rebuilt with new RP, syncros, etc. Notes from Previous Owner is that the car is "all original." Everything else on the car is. My understanding is that the 914/4 and 916/6 both used 901 based Porsche transmissions.

Question:

1 -Is 901 trans commonality correct?

2 - Does anyone have a /6 with trans # missing on the CoA and /4 markings on the transmission?

3 -What could be explanation for this set up on my car.

Thanks in advance for any help