I don't see why any blue steel gun wouldn't be engravable. That's usually the easiest of them all. I've even engraved a titanium Taurus. I use Lindsay carbalt engravers for most everything.
Hello Mr. Powderhorn, I have repaired and reblued many a tarus handgun and they are usually soft.
Compared to a smith and wesson stainless revolver where the barrel and cylinder are usually hard.