They look like the original vectors. These are no longer supported by Garmin. I have a set which were one of the first released for sale. I have had no issues with mine and they have worked well even though they have been moved from bike to bike many times. I recently lost a battery holder / cover. I emailed Garmin in Germany who got Garmin Australia to call me here in NZ. The Garmin guy needed my serial number from the box (it wasn't any of the numbers on the units). I explained I didn't have the box since moving from UK to NZ. He found me on the Garmin stats website and from that the number for my pedals. He then said that there were no spare covers shown anywhere in stock but that he could upcycle one from a returned and replaced warranty claim. He posted it to me in NZ all FOC. So in summary, nice unit that works well, shit that Garmin has dropped it so quickly after moving to the Vector 2 units, fabulous customer service.
I don't think they work with anything pre 810 but the best thing to do is take your head unit to the pedals, tell it to detect powermeter and spin the pedals for a few seconds. If it works then I would say these are a good buy. Mine cost £1200.