Tim,
Turkey is actually member of the JAA. Membership in JAA does not imply mutual recognition either on maintenance (JAR145), operations (JAR-OPS), licensing (JAR-FCL) or any other JAR. The states are assessed on the implementation of each JAR by itself. It is correct that Turkey has not yet been recommended for mutual recognition of licenses (JAR-FCL).
However, an FTO located in Turkey (or in the US or on Coconut Island or anywhere else) might obtain an approval from the NCAA of one of the states that
are in the JAR-FCL "league". If the FTO claims this is the case, make sure to always obtain a copy of the approval document (Standard doc. 153)
before spending any money at the FTO.
But, as there is no such thing as a JAR-FCL seaplane-rating anyway, I think this whole discussion will be of little use to anyone, I'm sorry to say.
Cheers, and happy splashes when youv'e got your (national) seaplane rating!
Redbar1