Only near the end of life when they were stuffing a few A500+ motherboards in the A500 cases, as I understand it, and then the A500+'s.
I never heard of any revision 6 motherboards being shipped with 1mb of ram, even though they obviously designed it specifically for that. However it would conflict with memory in the trapdoor and they didn't include a clock on the motherboard. So I doubt they shipped any with the memory on board and I can't see them fitting a memory expansion to them.
The revision 8 in an a500 case was down to marketing as far as I can tell. For some reason they didn't launch the a500+ in some markets. It turned up in the UK early due to the last a500's being on a ship when demand stripped the supply in the run up to Christmas, all they ready were a500+'s that could be put on a plane. These did ship with 1mb of chip ram, and with kickstart 1.3. I wouldn't bother with an a500+ though, an a500 with trapdoor memory expansion is fine for floppy games. For anything else an a1200 is better.
