Doubt it. Stat phones were digital long before cell phones were and the Russian government would not have sent a backup communications system without some serious encryption. Plus any good agent or source being debriefed by an agent would have gotten all of the particulars. I'd look elsewhere for a leak. Such as closer to home and someone with an ax to grind.
Using a secured by encryption radio transmission would wave a large red warning flag. If you doubt this you have forgotten the history of for example PGP and Phil Zimmerman. If all the trusted partners in the ISS can't listen to the conversation there would be a problem.
The Satt Phone in the Locker was good insurance for them against not being able to call home, but to keep a secret from everyone else would take something such as a Laser Satellite link.