There is only one model. The cr stands for choke regulated, which the A3, A3.2 and A308 all were. Some use the designation in there adds, some don't. I have had all 3 in the power amp versons and both the A3 and A3.2 preamps. I have never had one of the integrated amps which also followed the same model numbers. In my opinion, these pieces are great bargains on the used market. I enjoyed them very much.
I hope this helps.
Regards,
Paul