They use a 250K/500K mix .... 250K volume, 500K tone. I think the original Fenders were 250K/250K but I'm not positive.
http://www.fender.com/support/diagra...190209CPg3.pdf
The 250K/500K are readily available these days from CTS through Allparts or if you feel inclined we have them in stock as well.
Should you feel inclined to have a 250K/250K we can make some up for you.