No they're not.Actually, they are correct.
"1st Gen" refers to "First Generation Ram". The Ram line started in 1981 and ended in 1993. The earlier Diesels were in Dodges, but not in Rams. If you want to get nit-picky and start talking about the first Diesels in Dodges, then you have to go way back and look at some very early medium-duty trucks the Dodge Brothers manufactured.