Stopped in at one of my LGS this afternoon and the owner showed me a Model 18-3 with a 8 3/8" barrel, TTT, Serial number was 5K74XXX.
The revolver is basically unmolested, bright shiny bore. All numbers match, no evidence of having gone back to factory for any work. At least 95% condition maybe more. Lock up and timing very strong.
I've never seen a model 18 in anything other than a 4" barrel length. Shop owner says it has to be a factory special order. He's been in the business for over 40 years and has never seen another one.
Does this sound reasonable? I know a letter would establish precicely what barrel length it shipped with.