I never heard of a model 438. You made me look it up.
I see it's a model 38 with a stainless steel barrel and cylinder, but colored black to look like the regular Model 38 Bodyguard.
Cool.
I've had two model 38's over the years. One blued steel over black alloy frame, and the other a stainless steel model with a satin nickel frame.
Good luck with your search.