Larry, the Mangusta is a simple 3 position (off, run, start Magneti Marelli Q148C) switch. I thought that maybe Fiat 600 added the accessory position (the 4th position), but I think its likely that any transition to the accessory position happened only in the mid 70's and so then were probably ALL attached to steering column mechanical locks...At least, both Fiat 124 up to 1974 and Fiat 850 1972 were still 3 position only. The Goose accessories are mostly wired to operate all the time (and well, that means the window motors…but oddly, not the courtesy lamps in the front trunk and engine compartment, so as I can tell the ignition had to be ON for these to be used, and my experience was that leaving the ignition ON and motor stopped makes smoke if the points are closed.
The Q161 seems to replace the Q148, I cannot really see a difference (and even, association to the "G" key isn't clear..
A couple choices that appear to be right (one clearly the “F” key, the other may be…Lee
https://www.ebay.com/itm/174899704956
https://www.ebay.com/itm/274104172630