I've used some unmarked/salvaged modules in the past. Just used the first pinout I found (Nigel's PIC site), 5 volts, and a 38kHz carrier. Of three I've used so far, none have failed, all from different devices. Pretty sure unless you are doing something precise, should be close enough. They are only a buck or two new, with a datasheet... Not really worth chasing around the web. I used my Osciliscope and the TV remote first time I hooked it up, to see if it was working. 38 kHz is a good target, but give or take a couple of k's will be okay. I used mine for proximity detectors (about 3 feet).