Not exactly.
The 14-15 salary cap is now projected to be at $63.2 million. The Kings, minus Gay and Thomas, are projected to be at somewhere like $47 according to Sham. But that's not quite right, because Cousins' max extension is based on a percentage of the cap, and is not a hard number. So Cousins' contract will increase along with the salary cap, let's say to about $15 million. So the Kings have (assuming they pick up Acy's option) $49 committed before dealing with Gay and Thomas.
Oh, but then there's the 2014 first round pick. Another $3 million, so now we're at $52. And then the QO/cap hold for Thomas, which is around $3 million according to Cap'n above, so then we're at $55.
So, we only have $8 million to play with if Rudy walks, and that's assuming that we could sign someone before having to deal with signing/matching Thomas (who we re-sign over the cap, I'm assuming, based on Bird rights?).