Looks like you have one of the most desirable 44 magnums; a four inch possibly shipped in the first year of production. You'll need to confirm the ship date to know for sure (letter available for $100, see links here on the forum as to how to get one; will provide original ship to address too) as these didn't ship in sequence. I have SN S161859 which shipped in November 1956 (first year). Looks like a very nice gun in excellent condition. Also known to collectors as a "pre-29" as these became the Model 29 in 1957. Did you also get the box and tools? The whole package in the condition we can see is likely valued in the $4000+ range. Only about 200 of these 4 inch guns shipped in 1956. Very, very, nice and welcome to the forum. I noticed your Woodinville, WA location, use to live there back in the early '80s. Any other S&Ws in that collection? Oh, and great pictures too! There's a "search" function at the top of the page, just enter "44 magnum" or "pre-29" there and you'll find many previous threads about the 44 magnums.

Jeff
SWCA #1457