Similar to the Cadbury promo album I posted earlier this month is this groovy 7 Up album:
Dig that far out artwork, man!
A bicycle wheel? Perhaps this was a prize for paperboys? :p
I've looked up what they mean by 'rally caps' and it seems to have been a 'look under the cap' contest type deal.
Here are a couple of vintage examples, both being from the early 70's:
