Clamagore is the only GUPPY III known to exist. There were only nine of these conversions. Here's a summary culled from wikipedia, navsource, etc:
9 boats converted 1961-1963
Clamagore, museum ship in Charleston: 1981
Cobbler, to Turkey as Canakkale: 1973, decomm: 1998, another sub now has this name. fate?
Corporal, to Turkey as 2 Inonu: 1972, decomm: 1996, scrapped at a later date.
Greenfish, to Brazil as Amazonas: 1973, decomm: 1992, scrapped: 2001.
Tiru, sale to Turkey cancelled: c.1975, sunk as target: 1979.
Trumpetfish, to Brazil as Goias: 1973, decomm: 1990. fate?
Remora, to Greece as Katsonis: 1973, decomm: 1993, scrapped at a later date near Izmir, Turkey.
Pickerel, to Italy as Primo Longobardo: 1972/77, decomm: 1980, sold: 1981, another sub now has this name. fate?
Volador, to Italy as Gianfranco Gazzana Priaroggia: 1972/77, decomm: 1980, sold: 1981, another sub now has this name. fate?
As you can see, the fate of four of the others is apparently unknown. Given that almost thirty years have passed since Pickerel and Volador were decommissioned, and given that there is no sign of them anywhere, I think we can assume that they were scrapped. Trumpetfish might still be down in South America somewhere. The best chance for another survivor is Cobbler since it was decommissioned only eleven years ago (it was in the Turkish Navy so the folks in Little Rock might know something... having acquired Razorback or "Muratreis" from them just a few years ago). There's also a chance that one of the boats listed as scrapped is rusting away somewhere.
-FER