Going to be contrary here. You say the kid prefers playing RHP, LF, CF, RF, and 1B over playing C. In that case, unless his catching skills are needed to make the team, I'd leave the gear at home. The problem is that in a big workout like that the coaches need to see a lot of bullpens, and your kid could end up in the squat all day catching those pens, when he'd rather be getting reps elsewhere and throwing his own pen for the coaches to see.
If they are short on catchers and need a guy to step up during the season, that's a different story.