The finish on the V-1 sure looks and feels like polyurethane, but it has some finish cracks, which I guess can happen. I don't believe that many Mosrite Ventures-style guitars were given a black finish at the factory, but according to the database linked below, V0522 (three numbers away from my guitar) was also given a black finish.
SOURCE: https://hang10.de/lists/mosrite-venture ... res70-74v1

I took some measurements and the body of the Kurokumo is considerably smaller than the V-1, but the neck on the V-1 is wider and flatter. The Kurokumo is also much lighter than the V-1.
WAIST
V-1: 9.25"
Kurokumo: 8.75"
BODY WIDTH
V-1: 14.75"
Kurokumo: 14"
NECK WIDTH @ ZERO FRET
V-1: 45mm
Kurokumo: 41mm
NECK DEPTH @ 12th FRET
V-1: 20mm
Kurokumo: 25mm
NECK HEEL DEPTH
V-1: 19mm
Kurokumo: 10mm
'90s Kurokumo on left, '71 V-1 on right:

Interestingly, the overall feel and weight of the V-1 is a lot closer to the Hallmark I used to own, which surprised me. I had assumed that the Kurokumo was more or less a carbon copy of a vintage USA Mosrite, but it's not (although the Kurokumo is a great-playing instrument in its own right).