I've never seen the Dodge regulator, but have heard that people use them on 850's where the regulator is mounted to the fuel rail. Your regulator, if it's mounted down by the rack, uses a pod style regulator like the one I linked to.
You're probably right, the tech would have never admitted he screwed up. You wouldn't believe some of the lame stories my techs tell me to try and cover there ass. Most of the time I'll re-do the job myself so I can see what really happened, since it's my reputation that's on the line.
If the shop owner did tell you those things ahead of time, you should have given them the opportunity to fix it. Who cares what the tech said. Obviously he didn't want to do the job again and work for free, but the owner makes the decisions.