Sorry for the slow response. I did not check these forums for quite a while…
The transponder is the new style.
In the course of discussion with a potential buyer, I determined that the battery is completely shot (thank you, potential buyer, for showing me how to test that correctly). So, I’m listing it here as-is for $100, and if I don’t hear from anyone within a week, I’ll send it off to Transponder Services to replace the battery and then re-list it.