So far, from past sales, it seems like the box these came in had both numbers printed on it, but the same 212-149 marked part inside. The one in the attached pic sold on eBay in March, so it seems they appear from time to time. Keeping an eye out. Thanks!
I also wanted to add that I found an old thread here where it was said that this cross references to an ECG561.
https://www.videokarma.org/showthread.php?t=262454
There is a used one on eBay, but I'm a bit wary that the pins being labeled differently, namely 2 of them labeled FOC instead of one being REF. Could anyone confirm that this correct?