In terms of extra equipment it really depends on what you are doing, if they want shots of the band then it might be a good idea to bring a little equipment. I think you're right in say it'd be a bad time to start learning strobes, but you might try bringing a reflector, just so you have the option of filling shadows in a little bit. Are you shooting black and white, or color? I've found that although proper exposure is always preferable you have a little more latitude with black and white film than with color.
As for rights I'm not very familiar with that process, sorry!
I did an album cover about three months back, and I too am an amateur. The deal I worked with the band was that I wouldn't produce more that one copy of the photos they wanted for my own portfolio, and they would always come back to me if they wanted more copies, or copies that are higher resolution than an album cover.
My only other piece of advice would be to get at least half of the money upfront, I had someone decide they didn't like the price we agreed on, after I gave them the photos, and they decided to pay me less than half of the agreed cost.
Good luck to you! And please, take my words with a grain of salt, I am no pro.