The Gretsch Rock 'n Roll kit also had twin 12's with a 20 bass and 16 floor. Very common from my memory until the tom mounting system Rogers developed allowed 12 and 13 toms to have the heads at the same level. That I believe was the breakthrough. Separate Swivomatic mounts could do the same thing, but the double mount really made the difference and the 67 era mount improved the ability to carry the extra weight of the 13-inch tom while remaining stable.
One of the guys who is a favorite among the crowd here, Bobby Colomby, used a Rogers kit with twin 12's on a 20 with a 16 floor in the early days, and them moved to twin 13's on a Premier kit.
Here's a Rogers with twin 13's from Canada. Wayne Brown on this forum has advised that 13's were the available size up there and it was common to see them and less common to find a 12. Some other double 12's included here as well.