Okay, maybe it would be good to clarify what 707s are or have ben in different military services out there:
1) commercially-configured planes flying as military tankers/transports/trainers (ex-civil 707s with the USAF
, the NATO (ex-Luftwaffe) 707s, the former USAF
Air Force Ones, planes converted from civillian to military, eg. IIRC the Italian air force, Israeli air force and formerly Canadian air force 707s). They are commercially configured because, if I understand correctly, it wouldn't be to hard to make these planes into commercial planes, or they were already. Note that Iranian air force 707s which used to be tankers are now serving as airliners. Note also that the E-8s are converted from such planes.
2) military-configured planes built very specifically as military communication/tanker aircraft and probably harder to turn into airliners. 93 of these were built, the majority E-3 Sentry aircraft, but also 16 E-6 for the US Navy, 8 KE
-3A tankers for Saudi Arabia, and one aircraft which I think has been a Grumman test aircraft and designated YE-8B, but which I think became or was used for some time as an E-6. I AM
WHETHER THESE AIRCRAFT ARE CLASSIFIED AS
707-320, 707-320B, 707-320C, 707-700, a combination of this, or none of this.
3) aircraft which look like 707s, but are not. Namely the KC
-135 tanker/transport, many of which were built and which carried the Boeing model number 717 (and some the model number 739).