That's the part number, not a serial number.
I'm borderline mechanically incompetent and broke a punch trying to remove the right side safety lever before installation (also lever was going into a Centurion FS that I got off gunbroker and was beat to shit and filthy as heck, warranting a full detail strip, in depth cleaning, and spring replacements) but it took me longer to install the sear spring than it did to install the G lever. YMMV