I've bought from that seller before a few times (for my wife too) and they're awesome. Service, shipping, prices...and they have every vintage jersey you could dream of at one time or the other.
Ha...that jersey is from a kids' uniform set with the jersey, pants, helmet and shoulder pads. They're the itchiest thing you could wear.
I had a #10 one when I was a kid, Jay Schroeder. I replaced the burgandy Jay jersey with a #17 Williams jersey (in white actually).
So I invented white-on-white unirforms for the Skins.