Being solid colors id try to color match to the existing color on the playfield paint it into the missing areas building up layers then block sanding it all smooth once dry. Then do the black with a sharpie  then clear coat the playfield.  This work well if you have a good eye for color as matching is the hardest part. But im sure you already know this?

only things i could add would be to prime the bare wood first, so as to make sure the paint will adhere properly. And you have to be REAL careful if clearcoating over sharpie ink.. it nearly always runs under the clearcoat. i did this successfully.. ONCE!!  most of the times id tried it in the past the ink ran and i had to start all over again!! Very light coats is the key here i have found. I believe there some other brands of pens that work better for this than Sharpies, that wont run under clear coat.. i think Gavin (retropin) might be able to offer some advice in this department.

Hope this is of some assistance..

Cheers .. Mitch