Hello, thanks for the info. I did just purchase the 77 mark 1 and so far I love it. I use old Marshalls to play out, but have always wanted an older Mark 1 and just found this one. It's tan tolex with brown fender-looking grill, has EQ but no verb - has the JBL K120. I'm pretty blown away by what it does - it has a great dark tone - so far I don't have a grip on input 1, but input 2 is a great warm sound with just enough breakup. So far this thing loves Les Pauls, but also sounds great with a Tele.
What year is your Mk 1 and are you happy with its sounds? I didn't really buy it for the investment, but it seems these earlier models are only going up in value.
Best,
Marc