Many thanks again, Rabbit. I have treated a couple of painted surfaces in the pick-up cavities with the Minwax Wipe-on Poly, and they dried hard with no evidence of peeling or bubbling, so I might have been alright. But I will take your advice and clear coat with Rustoleum.
Neck is pretty well done with about 30 coats of TruOil. Not the best job I have done and the water-slide decal on the headstock did not go on as smoothly as I'd wished. But it has a pretty good feel, and that's most important.