69 BB identification...."PICTURES ADDED"

[YENKO DEUCE REGISTRY]

I think you've answered your own questions if you've got the invoice for the car, sounds like the real deal to me. I wouldn't worry too much about the core support, it sounds like the BB version.

Check the rear frame rail for the dual exhaust plate and look above the rear at the floor boards to see if the car has the rear sway bar supports welded into the floors - only SS cars and Yenko Deuces got them.

Welcome to NNN - great club! You will have to bring the car to Super Chevy NH and to North Country Nova's annual 'Nova Day' Epping.