I've asked the same question before and got a definitive "no". you'll have to get one from an early model as they are not reproduced...good luck.
I've heard people say that 69 will fit, but never have had a confirmed case with pics http://mmb.maverick.to/showthread.php?t=28190&highlight=mustang+rear+valence
Anything will fit anything. Seriously...just depends on how crafty you are. And how many metal working tools you have.