Disney doesn't even officially assign the DJ's until about 30 days out, and even then, contact is based on the individual DJ.
If you are concerned about it, I'd shoot your WP an email or phone call; they should be able to light a fire under your actual DJ to make contact. Ours was actually re-assigned about 2 weeks out, and everything turned out fine. I'd just be sure to have your music list ready for whomever the DJ is (intro songs, first dance, parent dance songs, cake cutting song, etc.).