Of course you can. If you have not received the final artwork yet and you wanna change the info you just have to contact us via email (firstname.lastname@example.org). Please, remember to place the order number in the e-mail subject line. It will be extra $5 if you want to change the info after you received the cover art.
Every cover art will get a sold out after 4 purchases. This is not a problem, just think in how many underground rappers there are around the world. Aye, million of rappers. The probability of you watching the same cover art being used by another artist is less than 0.05%. So you can be at ease.