No they don't.
Source - I work there.
We make our own glass, buy from Pilkington, PPG, Mygrant, etc if we don't have something, and they do the same with us, and we can get OEM glass from the dealer if requested, but it's $$$
The work is warrantied and if a chip turns into a crack, they'll credit the repair cost to a new windshield (ie, if you pay $100 for a repair that later fails and a new WS is $190, you pay $90).