Oak and maple for sure as well. I've have two combos cabs certainly made by Mesa that I wasn't able to identify but they were likely from the later Mark IV era.
There's always the chance someone screwed around with it, but those "Simul-class/Class A" plates don't exactly grow on trees so the simple answer is that yes, this is a Simul-class IIB. They didn't make individual manuals for each feature combination so I wouldn't worry about that part either...
Non-jokingly in the past you could get a IIB upgraded to IIC+ specs at Mesa, but they no longer have the parts. So you might be seeing different things depending on how knowledgeable/honest the owner/seller is. Could be a IIB actually upgraded to IIC+ specs (not sure if those we 100% the same or...
I could be misremembering, but I would swear I heard from people at Mesa directly that multiple Artists of the time wanted to return their original IICs before the plus (+) "fix" was made available. More anecdotal/second hand information, but it's been 35 years, there's more of that left than...
It's hard to read that serial, but based on the Send/Return I would think that is a IIB.
More info here on the serials for each model/year:
https://mesaboogie.zendesk.com/hc/en-us/articles/218914817-When-was-my-amp-made-
Funny to see a prices have almost exactly followed inflation. About $1,350 for a "fully loaded" hardwood combo in 1980, now it is about $4,000. The Mark V has a lot more features though.
Edit: Ignoring the hardwood option prices have come down a ton, but the hardwood upgrade itself has gone up...
I don't know that there is a full breakdown with every detail that was available back then, and speaking with people from Mesa that were around back then no one seems to remember every little detail either.
I can say for sure I have seen Mark II amps with Imbuia, Padauk, Koa, and Oak hardwood...
It's still up there. I'm sure he would attempt ship if I offered some crazy number, but I've already overpaid for so many weird hardwood amps no one was interested in I can't being myself to do it again.
FYI, Sweetwater now allows their customers to post ads for free. It's more like Craigslist than Reverb or eBay as SW isn't included in the transaction at all.
https://www.sweetwater.com/used/
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