Here's what I'm going to do:
1. Take it to my amp tech who is very knowledgeable about Marshalls. Have him verify that the capacitors are good and that the circuit is stock and just do a once over. I feel like, with an amp this age, it's just a good idea to have it checked out to verify everything is good. Also take gut shots so I can post here for your pleasure.

. If the caps need to be replaced, have that done and check the sound again through my current cabs.
2. Test out some tubes in the V1 slot. I've got some 12AX7's sitting around so I can check them through.
3. I'll take it and demo it at my favorite Marshall shop in Chicago (Midwest Buy and Sell) with some cabs there to see if I find its mate. I'm kind of kicking myself because two days ago, GC used had a beat up Bogner 412ST with G12T75's and V30's x-pattern listed for $299. I was seriously considering buying it but it had no photos. I emailed about it but they didn't respond. They ended up posting photos after the damn thing sold.
I'm quite certain I don't want to mod this amp at all and keep it stock. I'll certainly play it, but part of why I bought it was because I expect its value to appreciate over the next several years. I took money out of savings to buy the amp because it effectively acts as a bond for me.