OK, I started digging. They're playing around with real-life events.

Feb. 1981 - Russia started reissuing exit visas.
http://www.nytimes.com/1981/02/14/world/moscow-abruptly-resumes-issuing-exit-visas-to-jews.html

While in 1982, only 862 visas were granted during the first quarter
http://www.jta.org/1982/04/06/jewish-holidays/passover/soviet-jewish-emigration-suffers-as-passover-and-easter-approaches

That group of 1,500 could not have been in January 1982.

So in my head-cannon, I'm still assuming end of 1981 ;-)