Hello Carnut
The carby has been replaced at some point with a G3.
The original carby would have been a G2 with a cut-out wire running up the handle.
It was common practice to change the G2s with the G3s in service.
G'day folks,
I'm in agreement with CyberJack on this mower ID. As his pic shows, metal catchers were original equipment for this model.
It's quite clear that the G3 is a replacement, as the original cut-out wire is still in use, and the G3 cutout switch [the brass 1/4" tab] isn't connected. As CJ says, a very common swap, back in the day - G2 carbies were rather wear-prone, compared to the G3.