The Century Cetme and C308 are built using Cetme parts kits.
If memory serves, the C308 is built on a PTR91 receiver, so at least that is correct now. Hopefully they are using PTR barrels.
The cocking handle spring, the one that holds the handle down and out of the way is a common broken part in the Cetme/parts kits, but new ones for the G3 are available.
Try and stick with the G3 mags rather than the Cetme mags, less problems.
I am a huge fan of the G3/91 platform and have had several over the years and have considered building several once again but the build is not even close to the FAL or AR10 for ease of the build or maintenance.
The bonus is that Century is not building the Cetme like they once did, no bolt shaving, etc., and most of the problems today are due to the aging parts kits, just like the FAL, some are 50+ years old and with countless rounds through them before the demil process.
Stick to NATO spec brass cases, the fluted chamber and roller locking system are not kind to commercial brass and steel tends to give more bolt thrust, speeding up wear.