I know that there are records. Firstly, all (who are aware of it) receive a "Service" pension. Secondly, ALL who actively served in the second world war received a certificate of appreciation for their services. Many of my relatives received them and I have seen them.
The best place to start is the "Military Attache" of the Greek Embassy in USA. My guess is that the Embassy maybe responsible for the recipients of the "pensions" (Army veterans) in USA.