How to create Basecolor of Groom Asset used in Metamon

I’m currently trying to figure out the Groom used by Metahuman.

When Show → BaseColor is applied in Metahuman’s Groom Asset, vertex color information is applied.
However, if you import alembic through xgen or onatrix in a generally known way, the base color comes out black.
I’m curious how to apply information to basecolor like metahuman’s groom asset.