Holtons are not considered in the top ranks of vintage horns, not so much because they were inherently awful, but because they were not extraordinary in any one area, unlike many of their contemporaries. They were sort of the Ford Edsel of their day. Early ones like yours often had additional keywork somewhat in the spirit of the Evette systems with addition trill keys etc. These were really more of a nuisance than a bonus, and no doubt contributed to their disfavor. If you have to put a lot of money into it, don't expect to get it back when/if you try to sell the horn, as these aren't worth a whole heck of a lot to begin with. However, if you can get the horn up and running for a minimal amount of cash and difficulty, I would say that this horn will easily get your son through the first several years of playing, and will likely sound a lot better than many of the current production student horns out there as well. Cheers.