The plot thickens.
There appears to be two different base kits. In
this Imgur link there is a base kit with the manufacturer code "MDX-3571-BSKIT". The photos also clearly show white keys with black-and-white back sides.
My kit, however, has the code "MDX-3571-BSKIT
PBT" and features white keys with white back sides and surface printing.
This is not what I ordered.
Now I wonder if Signature Plastics has wanted to avoid making doubleshot international keys (lack of molds?) and just substituted in their DSA stock sublimated set in white and called it a day, hoping noone would notice. It's either that, or ridiculously bad communication between Massdrop and SP.