that's interesting. i knew that was the case on the modern airweights but was unaware they started doing this back in the 70s. so apparently aluminum frames can be blued, nickel plated, etc, same as steel frames? any word on how these older model airweights hold up compared to the steel versions?
Aluminum cannot be blued like steel, not sure if it is painted or anodized finish.
I have a model 37 from the 1950's and a model 12 (Aluminum K frame) from the 1970's. Both are black paired with a blued steel barrel and cylinder, both have signs of finish loss especially along the thin edges of the trigger guard and frame.
As for strength and durability I would NOT think aluminum (while lighter) would stand up to the punishment of shooting as well as steel (especially using hot loads) .
The older airweight models were also offered with a nickel over aluminum frame and nickel coated steel barrel and cylinder.
They look very nice but IMHO Nickel seems to oxidize faster on aluminum especially in a wet and salty environment (IWB holster).
I always wondered why S&W didnt offer a polished aluminum frame with stainless steel barrel/cylinder combination.
The newer versions are offered in black/black or a silver painted frame / stainless steel barrel and cylinder combination.
The silver paint wears off like the black but is much less noticeable.
Several years ago a new lighter version came out with a "Scandium" alloy frame paired with a TITANIUM cylinder (and barrel?) reducing weight even further.
I personally love them as a carry piece,
If your intention is to shoot it at the range on a regualr basis , I personally would suggest getting a steel frame model.
....Better yet get one of each.
Cheers.