Thanks, I did... with mixed results. Not everyone answered, some were sold out and one seller claimed he could not give me this information since the S/N changes on every tablet (even though I only asked to check if the 9th & 10th digits were V3 or V5)

I ended up ordering from here (EDIT: was sold out, after all). ATM it was the only Win 8.1 version I could find available and I figured the chances for V3 would be higher there, but let's see what I end up actually getting.)

EDIT: Seems like V3 are non-existent for now and even V5 are getting scarcer as many sellers reported having sold-out. Ordered one V5 (according to the seller) from eBay. We'll see...