So, I ordered some rubber bumpers, torx head screws and well nuts in sizes that I thought would work for this. Unfortunately the bumpers would require some modification to work but are the correct diameter and height. The holes thru the center washer are too small if going exactly as the original was. You could use a different well nut and an 8-32 button head screw and I think they would work. The OEM used a 10-32 button head screw.
Then I ordered this:
This is the real deal, from Jeep.
I've measured these and did a lot of googling. What I have figured out is this appears to be a somewhat common item and the trade number for it is 2093-W. It is 5/8" diameter, 1/4" tall, upper bore 3/8" and lower bore and washer hole 3/16"
I have found these on ebay in white and brown but no black. I will have to call a couple of the other companies that appear to have them to inquire on pricing. It's likely that I'd have to buy at least 100 of them to be able to place an order. It will certainly beat the $14 each that Jeep wants for them, and likely be fresher rubber than these that have been sitting on dealer shelves for who knows how many years.
Now onto the screws. A standard pan head philips or torx head 10-32 screw won't work. The screw head (0.133") will be taller than the bumper and hit the hood. What you need to have is a button head torx screw which the head is slightly shorter than a standard pan head. (0.101")
I will see where we can get these from and if it does end up needing to buy 100+ of these I may take the plunge if the price isn't too prohibitive and be able to help everyone out since there appears to be a limited supply of the $14 Mopar bumpers.