In the '90s, ruger made all sorts of "odd" variants of many of their models as regular catalog items. They also did some "distributor exclusive" version for certain large wholesale distributors too.
Does the plastic case still have the sticker with the serial number and catalog number on it?
I don't have a '96 catalog handy anymore and I don't see that version in the '94 catalog.
Your best bet would be to get in touch directly with the folks at Ruger to see if they have any information on whether it is a factory variant or not. They are usually a very helpful bunch of people whenever I've contacted them.