This turns out to be incorrect. The keys are uniform except for the thumb clusters, but not DSA. I came across this but of info on the MoonLander faq page:
“ What keycaps come with the Moonlander?
The Moonlander’s 1u (“square”) keycaps are OEM Row 3 profile, with the “line” keycaps custom-produced for the Moonlander. We also created the 1.5u vertical “piano keys” on the thumb cluster, as well as the 2u red “Launch/Any” keys specifically for this product. The Launch/Any keys ship with a costar stabilizer, which you can remove if you’d like (they’re quite stable without it). You can replace them with any Cherry-compatible 2u keycap, and replace the “piano keys” with any Cherry-compatible 1.5u keycap.
All switches are precision-injected out of high-quality PBT plastic, made in a doubleshot manufacturing process (i.e, the characters are physically baked into the keys, not printed). They’re made for us by Tai-Hao, a Taiwanese manufacturer of high-end custom keycaps.”