The cables will definitely hold 1000lbs. The tailgate should as long as the load is distributed.

 

That's not quite what '1/2 ton' means with pickups these days. The payload of a 1500 RAM is somewhere between 1400 and 1700 depending on cab and bed configuration.

Regardless of the payload capacity nobody is going to put the entire weight of an ATV on the tailgate at once. Even the largest ATVs (excluding side-by-side that wouldn't fit anyway) are roughly 800 lbs. With a rider you're under 1000 lbs. And then you split the load between the tailgate and the ground and/or the bed, depending where the ATV happens to be at the moment. It's likely you'd never have more than 50% of the weight on the tailgate at any particular time.

So, to put it in perspective... would you think two hefty (250#) guys sitting on the tailgate at the same time would be expected to bend it? I wouldn't

Rob