I value a stripped S. A. lower at about $15.
SA FALs tend to be ridden hard and put away wet, and the extra electropencil serial number doesn't help value at all.
I just sold a Imbel stripped UNserialed lower in good condition for $40
I just BOUGHT a stripped NOS Belgium made T-2 lower, unissued, unserialed, SED lower for $160.