I have a jack base that came with my 69. The only markings are a A-B, the A is much bigger than the B. Is this correct for this year?

Most had U69 on them, although some did not have any markings. The same base was used for several applications. Don't know about the A-B.
You did not ask, but the load rest had 69 on one line and Camaro on the other. Can't remember which is on top. Also, you didn't ask, but the mast is trapazoidal in cross section, is 32.5" long (+/-) and has a date code on a rivet on the mechanism. You can look at a pic on Rick's First Generation we site to see what the mechanism looks like.

Jack bases were a commodity, there were several suppliers. Most that I've seen don't have the U69, actually. Here's some:
http://www.camaros.org/kurt/69 jack bases compare.jpg

Yes, Jim, it's too wide.... :)