Exactly, pretty much everything starts out as Royal by the very nature of the TH tech distribution/dissemination pattern.
Now that said, since nothing on the Wolvie-II was actually NEW anymore, it could have been designed for Regular SLDF units.
However, since it is a "II" and a "variant" of an existing mech, I'm going to guess that it was intended for Royal units similar to the way almost every other "Variant" at that time was.
(Pixie-Special, Warhammers, Ostrocs, Locusts, Stingers, Hussars, Griffins, Shadowhawks, T-Bolts, Crusaders, Catapults, Marauders, Atlases, etc etc)
When it comes to Variants in the SL Era, you have some rare House Models, & some "early runs / Prototypes" before the "Mass Production" model, & lots of Royals, but you don't see many "2nd Version just as common" models for much of anything. Off the top of my head, I actually can't think of any.
Actually, there is 1, w/ no stats yet, the "Recon-Crusader w/ Jumpjets" that the Liao model was based off of which is likely some variant of 1 of the early 1R/2R Crusader platforms. Not that this one is "just as common" but at least I wouldn't call it an early prototype test run.
But outside of that I'm drawing a blank on most anything that would qualify as a true 2nd model that isn't House/Royal/TestRun specific.