The cap is on the bottom?
You're definitely looking at a relay and what appears to be a resistor. I wonder if this is just an RC delay wired into a relay. That doesn't strike me as a desirable way to drive a relay, but it might work, and I wouldn't be too surprised if an old component went such a route.
There's a partial model number there; [Nippon] Denso 61300-174-0[?]. Unfortunately, while I can find matches for "61300" that are indeed for blinkers, I couldn't find anything more specific. Physically, there seems to be a strong resemblance to a Denso 061300-6250, so much so that I wonder if that part would be a drop-in replacement. However, those seem to be crazy expensive. Honestly, I would recommend trying to determine if you can replace that kludge with a modern blinker module that's likely to be both a lot cheaper and a lot more reliable.
It might also help if you can work out and post a schematic.