I'm sorry that I don't have any helpful advice for you, although I do agree with DangerMouse about the highgloss paint. My husband used to paint wooden dinosaur puzzles with that.
I just want to say that I think it is FANTASTIC that you are trying to fix up one of your old toys for your son.

My oldest daughter has (and still sleeps with) a blanket that was mine as a baby (she is 16 now), and my youngest sleeps in what used to be my bedroom growing up (we bought my parents' house).
It is special.