You might have better luck posting down in the gen 1/2 forums. That being said, I think those have been out of production for a while as I feel like I've seen that same request on here before a few times. Viper Parts Rack (Jon B) and Don Scharf are the two places I would probably check first though. Parts Rack got all the old VPA stock, so if there were still any NOS parts in there, they should have it. Don Scharf is a salvage yard that specializes in Vipers, so they might have some good used pieces.
I bought one in September from Viperpartsrackamerica.com OEM but pricey. $271.46. I fixed my door stanchion to not break any more by threading a bolt into the hole intended for the side curtain retainer. The stanchion is now rock solid. The part you’re looking for is thin flimsy plastic and will fail again without this fix
How do you know if you need the Large Hole vs Small Hole. Looking at my car that has a broken driver side it appears small hole, but curious if Dodge ever made the Large style or it's aftermarket to fix a fitting / continued break issue?