Sturmgewehr 58 (StG 58). Whats it worth?

Evening gents.
What is a Sturmgewehr 58 (StG 58) worth?
Also know as a FN FAL STG 58.
Its not in the buy back list yet but will be eventually.

Thanks for your help.

Attachment 115918

Probably be classed as FN FAL. I have a C series G1 variant.