Definitely. EOL GPU's usually get listed well below their original RRP so it's well worth waiting for their sale. The 1080 and Ti variant are already being phased out by e-tailers so I'd wait till they try and clear stock.
The 1070/60/50 still have a marketable price point so they'll be sticking around a while yet. There's nothing to replace them with and to be honest, AMD will offer similar or better bang for the buck at their price range anyway.
A friend once told me a good tip to check for a refurb. Even though they clean the cards up well for resale, you can still see dust with an LED light. If it's not absolutely spotless, there's a good chance it's a refurb.