If the soda blasting or Dustless blasting doesn't remove old filler, you can heat the filler with a propane torch and pop it right out with a putty knife. You aren't going to hurt anything if there's an old dent under that filler....lol. If those trunk gutter pieces aren't available from AMD, you may be able to get some from @Lee Robinson on here. He sells nice sheet metal that he meticulously cuts from parts cars. It sounds like the one man shop you mentioned is a good place to get it done. If you'd like 2nd opinions, go to the Mopar show in Knoxville this coming Saturday (22nd) at Chilhowie Park over by Knoxville Zoo. There will be lots of pretty local to you Mopar people there. Myself included! :)