That is an eye-poppin' nickel 3-inch Model 10 Bladeswitcher!
Your revolver fires the imagination. I don't think I've ever seen nickel 3-inch Model 10 in person and don't recall encountering a photograph of one here on the Forum. Probably have and have just forgotten, but yours is bound to be one of the more uncommonly seen nickel variants of various Smith & Wesson models and configurations.
Thanks for the good photos. It's hard to take good representative photographs of nickel guns.
A factory 3-inch Model 10-6 lives here. It's serial number is 317,000-and-something which likely puts its shipment in the early 1971 time period. It doesn't have a threaded barrel shank. The ramp front sight extends farther down the top of the barrel than the front sight on your blue one does, but I don't know if that is an indication of anything.
The 3-inch with my old favorite 4-inch Model 10-6. I have its serial number committed to memory, D 362370, and a factory letter indicates it was shipped in June of 1971. I acquired it used in December of 1975 and it and its faultless service represents the original reason I'm here on the Forum.

Sorry about the ugly T-Grip on the 3-inch. I wanted to equip it with a Tyler T-Grip and one came along for cheap, but it was brass so I took a black Marks-A-Lot to it. Didn't really improve the looks and now the black is wearing off. Do y'all think it'd look better cleaned off? It'd be garish shiny brass then.
From this thread I'm getting the impression that the 3-inch Model 10s of the 1960s-mid 1970s era were uncatalogued items. Is that a correct assumption?