Yes, I'd say very good prices, especially for a late M3 in clean shape. I take it everything works properly -- shutter speeds; framelines; rangefinder aligned?

I'm sure you know this, but you will need an M adaptor for the J12, specifically one that brings up 35mm framelines since that's a 35mm lens. And only the M2 has 35mm framelines -- you would need an external viewfinder for accurate framing with the M3.