[prplhrtx3]

Just a guess, but my Defender is a model 07000DZ, it is a Colt Custom Defender. The box is marked accordingly. The regular production Defenders are model 07000D. Maybe the Z denotes Custom of some type???

 

[prplhrtx3]

I think my guess was correct. I just checked the box label on my NIB 01991Z, it is marked Custom 1991A1. Mine is matte blue, the one you are referring to model 01091Z is probably the same thing but in matte stainless. These are the Lew Horton guns, I can't remember what is custom about them except they came with a Videki trigger, may have some other features though..They have the billboard 1991 rollmarks..hope this helps..