I don't know if I was just blind before or what, but on Nintendo's investor relations site I found the links to the archived quarterly releases and other announcements. In previous times I tried finding what I could on archive.org but had huge gaps. The English one
goes back to FY2000, and Japanese has some stuff as far back as
FY1997.
Randomly picking
one to stick through machine translation, I saw something pretty interesting. Nintendo always considers GB+GBC to be of the same family, and so generally the shipment numbers have been combined. So we knew that through March 1999, about a half year after GBC released, Game Boy's Japanese shipments were ~23.96 million. But this announcement specifically breaks it down into 20.84m grayscale and 3.10m Color, which is at least to me a new data point. Probably not enough other statements like this across time/regions to totally separate GB and GBC, but I'm curious what else
is in there.
EDIT: Also worth noting, this information was in a release about the GBC dropping price from 8900 yen to 6800 yen. With a drop like that so soon after launch, you'd think it was the 3DS.
My current one I had custom built for a few grand in late '22, and that seems like it would run most games better than mine. CPU benchmarks about 20% better. GPU very similar except you'd have access to DLSS FG. I'm pretty happy with what I can do with mine, but I also spend more time playing older releases at crazy frame rates/resolutions than games that really push the limits. Starfield probably the heaviest I've spent much time in, with frame rates usually in the 40-70 range while using FSR or DLSS to go from 1080p->4K. At least, that's what it was before FSR FG became an option, and I've barely tested that out.