Unless your band has charts ready made, you're better off going to youtube, finding the song you need to learn and start playing along with it. This is a crucial skill for playing pop music, and if you're not good at it now, you can only get better.
Yep, what Grumps said.
If you're playing in any kind of contemporary band oriented around rock, pop, funk, soul, RnB, hip hop, and so-forth... you HAVE to get your ears in shape. The chances that the band leader of this tribute act actually has written parts for the horns are very, very small, and if he/she did, you probably would have seen them already. That means that, like most contemporary bands, they'll be expecting you to learn and know all your parts for all the tunes.
Maybe the horn section leader (if there is one) has written arrangements, and that would be a good person to ask... but even then, that horn section is probably going to want all its members to have ears that are good enough to hear and pick up harmony parts.
The ability to read music is almost inapplicable to many or most contemporary working bands, in my experience. Your ears are far and away the most important things in your tool chest. If you're not good at figuring things out by ear, make progress by doing steady daily ear training (plenty of fun apps like Earpeggio can help you get started).
Of course, I could be wrong about this particular group, and maybe they have great, clear charts for everyone! That would make them a relatively rare exception, these days.