The website doesn't say it is handmade, but handcrafted instead. Probably means it was made on the same assembly as other stingrays, and the aging done by hand.
From what I saw when I looked up he difference in the two terms, there's not much if any at all:
"It's definition of “Handcrafted”; to fashion or make by hand. Merriam Webster: Handmade; made by hand or by a hand process. Handcrafted; to fashion by handicraft. ... Handmade; made by hand or a hand process."
Handcrafted vs. Handmade.

