Looking for a birth year Chiefs?
I update my database almost daily. I don't post it anywhere. Roughly speaking I have about 1% of the Chiefs made for any specific era. That doesn't sound like many, but at 40 entries per page, the database is pushing 60 pages, and I don't have a ship date for every entry.
It's hard to determine a "range" for almost any year Chiefs Specials. Since S&W didn't ship them in serial number order, the shipping dates are always a guess without confirmation from Dr. Jinks.
I've found the blue 2" round butts are relatively consistent in shipping order (not always), but a 3" barrel, a square butt, a nickel finish, an Airweight (or Model 37), a Bodyguard Airweight (or Model 38) a Model 49, and most especially a CST (Chiefs Special Target model) can be much earlier than the norm or far later (the CST's are usually much, much later). I don't have enough examples to make a firm estimation with any of these.
I'd guess (and that's all it is) if you look for a Chiefs Special Model 36 in the 200000 - 240000 range you're likely to find a '61 shipper. There are Chiefs and Bodyguards within this range that shipped in '62 or '63, and some of the '61 shipped CST's go back to s/n 150xxx.