"...does this mean its good to go?..." Depends on when the FTR was done. Before or after the ZF. Chances are the butt stock was a salvaged stock. Mr. Laidler, on the 2nd page of the milsurps.com link(BadgerDog is right. Long, but informative discussion. Worth the read. Slow site though.), says any 'ZF' rifles were destroyed before being sent to the scrap metal dealers. Salvaged rifles wouldn't have the 'ZF'. I'd bet your rifle is just fine, but has a salvaged stock.
Have the rifle's headspace checked, in any case. Matching numbers doesn't guarantee that the headspace is ok.