From skirmishes in the 1990s crypto wars I can assure you plenty of open source software was export controlled.
In fact this was a drive for some of Cygnus' overseas offices: not to evade the law but to do development that could not be spoiled by accidentally exposing it to a person subject to export control laws. Stupidly, we could import that software into the States, but people there couldn't fix bugs in it, only file reports.