OK, here's an update, geeeez this is turning out to be a royal pain in the . . .
Called Gemplers, gave them the part numbers on the invoice Simp included above. Nobody knows what to do with those numbers. I ask for Tech support, they say it is a non stocked item and they will call the manufacturer and call me back. 5 hours later, no call. I call them back looking for answers, I can sense the deer in the headlight look even over the phone. Still no answers from Gemplers.
I then called Haltec and asked them about the O-rings for a second time. I couldn't get anywhere with customer service so I asked for one of their engineers. This guy knew what I was talking about. Apparently the OR4201 is a number the military asks them to stamp on the o-ring. It isn't a Haltec part number. Haltec's part number is 524961000013. I thanked him and was transferred back to customer service. I asked if they had them in stock. They confirmed they did, but they wouldn't sell them to me, I have to go through a dealer. They gave me numbers for dealers. I called the dealers, and was met with what I assume was the deer in the headlights look again. Apparently Haltec's part numbers are typically 6 digits or less and giving them a 12 digit number was just way more than they could handle.
I then went to Eriks Military Surplus thinking this is way to painful, I will spend the $16.75 an o-ring to get this over with. I then went to check out and was met with a fee of $28 and some change to ship me the 5 o-rings. I just couldn't do it.
Why is it so hard to find suppliers for these o-rings? Isn't everybody changing their o-rings when they put new tires on?
OK, I will quit whining now.