I'm only aware of Universal sending out a PIN promotion once and that was back in February. Funny thing is, I didn't get the PIN email, but my wife did. However, we applied it to our reservation we had made back in January.
We're both annual passholders, so I'm not sure why she got it and I didn't. I'm thinking they excluded passholders that had an existing Loews reservation during the promotion period. Just a guess though.
To answer your question, I don't know...