Very common. I have never seen a Vegas book not offer 1st and 2nd halves.
They may skip over an obscure college game but as a whole they offer these wagers for college and NFL.
I suppose there could be some lower level books that don't offer halves but I have never seen it.
Spreads and totals only.
Oddly, I have never seen any Vegas book offer first and 2nd half Money Lines. You see it all the time offshore, I have never seen ML halves in Vegas, the exception being the Super Bowl.
