Kind of long-winded, but.....
The green gear you showed in the picture appears to be for the output shaft of a 2 wheel drive transmission.
I did a little digging through my parts book, and on the web, and came up with this:
E0TZ-17285-C BLUE 7 Tooth
1984 F-series NP208
1985 F-series BW1345

Not sure where in Az you are, but Babbitt Ford in Flagstaff, as well as Don Sanderson Ford in Glendale, supposedly have them in stock (although they might have them listed as E"OH"TZ instead of E"ZERO"TZ).

If you're up to making the drive, you might see if the parts match what you need, without having to blindly order something over the web.

Not sure if this will help you, but it might be worth a try.

P.S. I have seen on occasion, the gear would be "faded", due to age, heat, etc.