Well, no sooner do I start my blog and we get updated information, how cool!
These December 1955 tickets were sold on EBay yesterday (sadly, not to me), they appear to predate my post of yesterday. It looks like the very first ticket books we not denoted as "ABC" after all. They look like the early ABC tickets, but they have no letters on them. The red "A" is just part of the serial number. Notice there is also one "A" ride ticket book similar to my post of yesterday.
I spoke to the high bidder of these tickets and he agrees, these "non-lettered" tickets must be the first from the ticket books. Probably in use from mid-October to mid-December 55, at which point the "lettered" ticket were introduced. The booklets themselves appear to be slightly longer too, here is the backs of all, plus the "A" book:
P.s. In case you are wondering, I did bid on these, but, well, lets just say it went out "over my head"...