I've learned to "Never say Never" where muscle cars, guns, and some other things are involved. It does look like a refinished model 19 to me. Both my model 66 no-dash 66s had stainless ejectors and standard, not target, "flash" or hard chromed hammer and trigger. While my early '70s blue model 19 had a target hammer and trigger, the only early 66 I've seen with target hammer and trigger is my 66 no-dash that was electroless nickeled by Robbie Barrkman. My blue 6" model 19 had the same Patridge type front sight, as opposed to the ramp type on every stock 6" model 66 I've ever seen.
But, a letter might prove you have a valuable collector's item, an actual stainless model 19. Never say never...