I don't think there is anyone that can say yea or nay with 100% conviction, but I can say I've used pretty much exclusively third party cables for all of my precious iPhones and never had issues. Cables fell apart eventually, but never damaged my phones. In short, I wouldn't worry about it.
I've got a genuine apple lightning cable, and a 3rd party one bought off eBay. Guess which one fell to bits within a few months and guess which ones still going, still not horribly discoloured and still charges at a good rate?