I thought my Mopar indicated it was Dayco??
Watch eBay, the guys that have the Dodge exhaust brake installed at the dealer often need that belt replaced on a new truck... often you can get a low mileage belt shipped to your door for under $20... that's what I did and have almost 90k on it now without issue.
I also carry the old one as a spare... they might not deteriorate, but they do wear out (the grooves wear into the belt)...