Well well, would you look at this.
https://www.eevblog.com/forum/buysellwanted/fs-siglent-technologies-sdm3065x-6-digit-digital-multimeter/msg5026573/#msg5026573
Now $510 shipped with PP goods and services. Same picture.
EDIT: seller and I are having a conversation via PM here. I've not written it off yet, let's see where this goes.
I pulled the trigger on this after the seller and I worked out an agreement in writing for a reasonable return period in case anything is wrong with it, backed by PayPal. Seller was very accommodating and easy to work with, so kudos to Yinz/eDreamzWarehouse (eBay handle) for being reasonable with my requests.
Per the cal certificate, only a year or so out of factory. No guarantees of newer stock than that even coming from a dealer. Warranty repair might prove tricky if I ever needed it, but being it's apparently still factory sealed and if it tests okay during my return period, it's unlikely I would need warranty work before the warranty expired anyway. Crossing fingers, anyway.
When I get it, I'll run it through my assortment of cheap AD584 and LM399 references and my LB02A process meter, and compare to my Agilent 34401A (long out of cal but has remained very stable from what I can tell) and maybe the BM869s. This is just for hobby work and doesn't require a high degree of calibration certification, so if it tests within spec along with my other devices I'll be happy. At least if they're out, they'll all be out together.
Assuming it performs as any other new unit would, $510 delivered for a brand new SDM3065X is a pretty decent score I'd say. Will provide updates here on the outcome.