Looks like ash, which is a bugger to gloss due to the open grain.
Filling the grain so that it looks right and provides a flat spraying surface is tricky.
As said above, the grain can be filled with initial clear coats, then sanded back, repeat until no low points, then lacquer as normal.
But there's a risk of sanding off the red stain in parts - then you're screwed.
If your man can do this for £130 bite his hand off, but be ultra sure he has seen the bass in the flesh and is confident that he has the experience to to it properly.
Let us know how you get on