My bandmate has a new Gibson semi-hollow body Midtown bass and I think the strings are hitting the metal pickup cover. Just by eyeballing the current heights, they look to be about 2/32" away from the string when the string is fretted at the last fret. He's cautious about changing anything because that's how it came from the store. What's the general height guideline for pickup heights on passive pickups? I'm thinking it should be about twice that much (4/32"). Any opinions appreciated.
1/16" is generally too close for bass strings IMHO, I'm with you. Even if it's not making contact it's probably affecting the string's vibrations magnetically and I also find it hard to get a good volume balance from string to string when they're that close.
They make basses adjustable for a reason and music store employees are rarely experts. "how it came from the store" is of exactly zero value, especially in the kind of sudden heat and humidity we've had in New England the past few weeks. Tell him to be brave! Make small changes and write down exactly what he changed so he can change it back if needed.
If all else fails have him watch this at 6:35 or so. It's a rare gig when I don't feel the need to adjust my pickup height after the first song or two. I've also been known to tweak my truss rod and/or action between sets. Everyone should know the basics of doing an instrument setup IMHO.