If that actually reads GJAB, you have correctly found the prefix of the serial number. Meanwhile I've now broken the code on the plant identifications. The GXV140 and GXV160 both use a weirdo prefix to the serial number instead of using the model name, as older models seem to do. GJAB is the serial number prefix for all series of GXV140 engines. The GXV140 has been out of production for years, and was only ever made in USA. GXV160s over the years have been made in Japan, the USA, and China (lately, mostly China). If you post the serial number prefix of your GXV160 I'll tell you where it was made.
