Identify a Spirit of 76 truck

[68 50th]

I have spotted a 76 K20 Bonanza that could be a Spirit of 76. It does have the inside door 76 emblems, white door panels, blue dash pad, body colour is white no red and blue stripes and the seat is covered so it is not possible to see how it looks. The ad says nothing about a Spirit truck.

Is there a way to identify a real Spirit of 76 truck by any RPO codes? Is there a specific RPO code that says Spirit of 76 or something. And/or do they need to have a specific paint code, trim code or could they come in several different colours and trims?

Have searched and found some info about the Spirit trucks and other special edition trucks but nothing about the RPO codes.

Thanks