It depends if you want blued frame to painted/parked and a other little differences. All restricted barrels are chrome lined anyway. Some people will tell you FSN is a better rifle, while I have had almost 0 problems with my restricted CZ with thousands of rnds put thru her.
$500-575 range is the most I would spend on a used CZ. for 100$ more you can buy new almost. Ask for bore pics when and if you do buy used. SOme people say it is in great shape, but then the bore is pitted and rusted to s**t.
Hope you do get one as the 858's are a great platform of rifles.