The A6304XL has arrived!
Overall it's in very good shape cosmetically. The carrying case is pristine except for what was probably an asset number written in sharpie, which I chemically removed. The foam inside had completely disintegrated, making a huge mess of everything including the probe. However, some careful cleaning combined with an air hose restored it nicely. There isn't a single mark or imperfection on the probe, cable, or connector that I can find.
The all-important core faces were in pretty good shape. I cleaned them up with some 400 grit sandpaper and they're ready to go.
JUST KIDDING. I didn't touch them, not even with my fingers nor with pressurized air. They appear to be perfect, flat, and unblemished as far as I can tell without optical measuring equipment. The foam "dust" didn't get inside the jaws so the core faces and the epoxy in which they're embedded were clean.
The cable was sticky from foam residue but that cleaned up easily. The gold contacts are straight and still have their gold plating.
I can't actually test it until I get an AM503B (this probe unfortunately requires the "B" version). But so far I can't complain for $52 delivered.
This sidearm-style probe has a mechanical lock at the back where a traditional sidearm's hammer would be located. Given the rather long distance that its jaw opens, I expected that the core faces would retract apart to protect themselves, then actuating the lock would squeeze the closed jaws together to achieve good coupling. However, it doesn't appear to work like that which suggests the cores just scrape across each other {yikes} in normal operation. Does anyone know if it was supposed to do a retract/squeeze, and perhaps this one is aged a bit? Or do they actually intend for the faces to scrape?