pretty sure that is an example made by a luthier that I have purchased two Explorers (see my avatar) from but the current YJ seller is not the builder.
The builder recently sold (10-6-23) another Flying V Jr. made with African Khaya in a natural finish; looks really nice.
Neck thickness @ fret 1 was advertised as 24mm aka .945"
My Explorer Jr. made with Honduran hog is pretty amazing and with a huge neck