Duff - Sorry. I didn't mean to alarm you as well. Just wanted to say your rod looks like my SF rods (save the reel seat and grip). When I get home, I'll check out my stash and post a photo or two. And like you said, Tom Morgan would have the definitive word here.
Kab's linked post shows the difference in wrap color between his friend's SF and MT rods, although my memory may have it backwards as to which one is candy apple red vs. maroon. Winston may have switched thread choice though even prior to the MT move.
As for no catalog documentation of your specific model, Winston has been known to make custom configurations. Perhaps yours? I have a SF era 7'0" 4 pc rod that is either a 3 or 4 wt, that I've never seen cataloged or mentioned before. [Unfortunately, it's missing its tip section, so I'll never know what it can cast, but the taper is obviously much smaller than a 7'6" 5 wt rod I have. Incidentally, Glenn Brackett and I have been talking about making a replacement glass tip or even fitting a cane tip for it just for fun!]
Personally, if I could choose between a SF short 3wt vs. a similarly configured MT Stalker, I'd choose the SF rod as it likely would be a little crisper in action and not nearly as common from a collectibility standpoint.
Congrats either way! Nothing like a little post-purchase drama to add to the fun!