Did Pontiac build a 66GTO with a 237 vin which would have been a continuation of what was done in 64 and 65?

No. All 1966 model year GTOs were 242 cars. If someone is selling a 1966 "GTO" and it has a 237 vin, it is a fake.

Agree with the above statement in 1966 Pontiac GTO hadd a VIN it will start 2 for Pontiac and 42 for GTO. That was the first year they started the VIN and GTO as a car not a option. If your in doubt order the PHS Pontiac Historcal Society pack it’s 65 bucks but will tell you everything about the car. It is too easy to clone a Lemans and Tempest to appear as a GTO and the market value of one now is a huge difference. Don’t let someone get one over on you.