Hercumatic was just rebadged Sturmey-Archer.
Since it has a hub, ask for the serial numbers on the hub. That'll give you the date of the hub. But as I said earlier, I didn't see a shift cable or shifter.
I bought a Raleigh Ltd.-3, a very similar bike, for $10 plus $50 in shipping, off eBay. Looked a whole lot better than that Hercules. I'd pass on this bike.