I spoke again with the former owner last night. He's checking for any other paperwork from the sale. This Camaro was ordered in the fall of '68 with the head restraint delete option. It came into the dealer that way. I may have better documentation soon. While I've checked beneath the seats (both front and rear) I've not checked behind the rear seat back for the build sheet. I've heard that the Van Nuys plant was know to place them there as well. I will be checking there this weekend. Hopefully I'll find it.
In speaking with the former owner I truly believe him to be an honest and very up front person. I'm beginning to believe it is a AR1 RPO.
I checked to see if there was a head restraint mounting plate below the vinyl, and could not feel a mounting plate or plug, but without removing the seatback cover I can't be 100% sure. There was nothing 'solid' where I thought I should be able to feel a solid retangle shaped object. I felt a lot of seat cushion.
I hope to find the build sheet this weekend, or the sales sticker from the former owner.
I'm just not yet ready to say that it is an AR1, but all that I've heard and seen so far sure points that way.
I sincerely appreciate all the help with this!