I like first year '61 Navy's a lot (all '61's for that matter) and have 3 originals, plus a 2nd Gen and a Signature Series. One of my originals is in slightly better physical shape than yours (all matching numbers with no "add on" parts) but it's also been heavily buffed to clean it up by a previous owner. I can still read the numbers and the barrel address and patent but the cylinder scene is gone and some edges have been rounded. I gave $1000 for it a year, ago swapped out the nipples and use it as an occasional shooter. Knowing the condition, that's what I bought it for. I could see yours going in that 1000-1500 range as well - no offense intended. There are people who would pay more just to have a first year '61 but unless it's got matching numbers, original grips, or an amazing history, etc there's not much true collectibility, IMO, because of the fact it's been altered. Can you post more and detailed pics?
For reference, my other first year '61 was shipped to the Boston Navy Yard in October, 1861 (yes, paid for the letter on this one) has a shiny bore, good cylinder scene, all matching numbers (including the grips numbered in India ink in the channel). I paid $2200 for it two years ago.
My fully loaded an capped dug/relic '61 that I recovered from private property at Stones River in the early 1990s was shipped to JC Grubb in Philadephia in November, 1861 and carried by a member of the 15th Pennsylvania Cavalry and lost on December 29, 1862 at Stones River. With Charlie Pate's help over the past 30 years I believe I have narrowed it down to two possible soldiers, both majors killed at Stones River, who MAY have carried it. This one is priceless to me.
Please post more pics and lets see what's what to better help you out. Thanks for sharing your early '61!