FAL rifle parts kits are legally sold with the lower intact which includes the full auto hammer trigger sear set. The original upper receiver, which is the controlled part, has a part that allows those parts to function full auto. The kits that I have seen only retained the front portion of the upper receiver where it was threaded to the barrel. The semi auto receivers or upper receivers which are legally available domestically have a filler part that prevents the hammer trigger sear from functioning in the full auto fire mode. While I am not familiar with the SAR 180, I am guessing it is a similar configuration.