Hi OP,
Value is going to be dependent upon components, condition, configuration. Pics would be helpful. We would need to know the make of receiver...Brazilian IMBEL, Argentine Rosario FMAP, Century's own. Is it still in thumbhole configuration as Century Assembled? If not, what had been done? Is it working 100%?
My own Century L1A1 has been an off an on project for way too long. I grabbed my own rifle because it had all British parts, a complete maranyl furniture set, an Argentine receiver, and was less than $400 back in 2014. Sadly Century trashed the bbl(the flats were totally buggered), the locking shoulder looked a bit worse for wear causing me to doubt headspace, and a previous owner put some flavor of DSA hider on the chopped/shortened bbl.
In the current market FAL's are often worth the price of their parts.
HTH
Blitz-