Looking at the dealer one for $5450 I note the following...
- Named with civil war name/unit engraved on it (add mucho dollars)
- Appears to be in orginal box with original tools
- Complete mold
- Original flask
- Reportedly has excellent cylinder engraving.
- No mention of bore, nipples, safety pins.
The dealer sites which I have seen the 1849s on regularly list these revolvers for 1300-1800 with no case etc. The $1800 ones I have seen are comparable in condition to the dealer one you linked (less the naming). Again, these are dealer prices.
A cased, engraved Tranter with Canadian pedigree sold on the EE about a month ago for 2k. The same guy had it at the Edmonton show the month prior. Think it was missing the loading arm but nice historical Canadian piece in original named case. The same guy had an 1849 listed that needed a spring I think. I would have put it in the Fair-Good category (he had that at the show too). He listed it for $1350 and sold it (although I am not sure for how much in the end).
I have sold guns at gun shows with my buddies and they think I sell them too cheap. The difference is they always have to lug theirs back home at the end of the show and for the sake of $100-200 dollars I am ready to buy some new stuff. In your case, without handling the revolver and inspecting it up close, I think I am being realsitic vice conservative.
I could be out to lunch though...you never know what people will pay! Like Wally said, list it for whatever you think you can get and adjust depending how bad you want/need it sold.