That sounds like a pretty good opportunity to me. Most photographers get their starts (like me) from working at studios, or for other photographers, for low money and then take what they learn and apply it to their own careers. The other thing to keep in mind is that being a professional photographer is only about 25% taking pictures, and the rest is sales, organization, client relations, etc. You'll get a insiders view of all that, which is priceless.
If you're working for a studio, someone else has gotten the client or account, then come up with the concept, and then taken the risk to set it up, so not having the rights to those photos is not that big of a deal to me. Spend some time in a working studio, and you'll see that focusing and shooting the cameras is usually the easy part of the job.
David Buzzard's Technical Blog