The registration number has shown up online, though I don't have the page in the mail. So I put the numbers on. First one, I had set it down on the dusty h-stab before taping it up, so it's got some dust in the adhesive. The second side, I realized what happened, and wiped it off before taping it up. Also stuck the "Experimental" sticker where it may someday be covered by upholstery. At which point, I'll probably have it embroidered right into the upholstery.