So I took apart my Micro in search of the yellow tag. It was dated 12-5-77.
I removed some adult sized dust bunnies, but before I reassembled the unit, I noticed a couple of things.
Printed under the main PCB near the Moog logo was “MF104” in a unique font.
Also on the bottom side of the main pcb was a single capacitor. I wonder why this lone component?
There also seemed to be some fluid/goo leaking from below the switches.
My micro surely needs a good cleaning.
Eric
The capacitor was likely a mod to increase the bass.
Was the goo green?
More bass? Yes please
Rather than give inaccurate observations…
What is that, flux or something?
As far as I know, this is a second owner Micro. The guy who I assume purchased it originally in NY gave it to my father at some point. Was a bass mod something that the factory would do at that time?
Edit:
Okay, that isn’t the bass mod, according to MC’s photo:
I had some minor servicing done on my Voyager OS this past summer, and the tech who did the work found a tag inside dated June of 2006… I was positive production on the Old School model didn’t start until 2008. Anyone know what’s going on?
Did you see the tag?
The font reminds me of the “Mezzo Forte” annotation on music scores 
104 might be tempo in BPM 
Yeah I have it somewhere. I’ll have to track it down and post a scan of it on here. It wasn’t attached to anything, just a loose card that was floating around inside.