Not for the JW-14.I always heard some kind of CZ mag would work...
The JW-15A is the one you're thinking of, which is a clone of the Brno Model 2, which became the CZ-452 after CZ took over Brno, and has since evolved into the CZ-455....
The only reason I know that is because I have a CZ-452 Lux (see profile pic) and was looking for spare mags that didn't cost an arm and a leg (so far, no luck - but I bit the bullet a while back and just bought some CZ mags at $40 a pop, so haven't looked in a while).