Dave I had checked the cylinder (it is steel) once I heard about the alloy.
Good on you, guess you didn't need the advice. When you said there was "freckling" on the cylinder that indicated to me it was likely steel, but I thought it worth mentioning.
The Airweight Chiefs is a nice carry gun. It was a favorite of Bill Jordan, who knew a thing or two about revolvers. Good to know this nearly 60 year old revolver will continue doing the job for which it was made.