Your color matchprint/mockup and test disc sent together is called a “proofset.” The color matchprint/mockup is printed on a digital printer that is calibrated to behave similarly to the offset press. It is printed on plain laser paper (not the final stock) and is typically sent unassembled, but with the dielines printed. These items are FedEx’d to you. You need to check these carefully and e-mail us back approval to proceed to final production. There is no need to return these. Should you need to make changes at this point, the costs will involve graphics time and possibly a new proofset, if you require it.
If your schedule is rushed, other alternatives include a print-only test disc, scans of the disc or matchprint sent via e-mail, an FYI-Only viewing of the proofset (could save final product shipping costs), or bypassing the proofset altogether.