Well I have to say that I'm very surprised by that.
I have just double checked your photograph and it definitely looks as if the socket has a raised ridge in the middle and, when I compare it to the couple of AM3 boards I have access to, it doesn't look the same.
The only thing that I can now think of, is if a couple of the CPU pins had been moved slightly out of alignment when you removed it from the other board. If they had it could have produced the problem of wobbling and not fitting that you describe but the only time I have had this happen it has been pins on the outside of the CPU that have been damaged, not the ones nearer the middle.
It might be worthwhile sending your CPU to SCAN, as you suggest, as they would then be able to diagnose the problem properly.