visit cetmerifles.com and gun boards cetme fr8 forum.
as for centurys rifles or any breed,,, unless you can buy and inspect the weapon in person,, pass it up.
they arent very highly rated on the QC end of things, BUT,,,......
if you can find one that is in spec,,with parts that are not worn to hell and back,,you can have a rifle that is very dependable and accurate,
on cetmerifles,com/gunboards there is a list on ""what to look for when buying""
it takes you thru the steps on how to check bolt gap,,check for un ground parts ect. these can also be used on century 91/g3 clone also.
if i was standingin the store id ,,charge the action a few times,dry fire, drop in a gap gauge,, for bolt gap,,, ,, check for canted sights and go from there,thats all you can really do unless the shop takes it aprt for you or lets you do it!
good luck