If we're talking about an Intelliframe for a 'mag, then no, it doesn't come with a sear (it just uses the existing one) - if you want to hook your hopper up to it, you'll also need to buy a microswitch from Maplins/Radioshack (depending on which side of the pond you're on).
They're worth getting just for the comfort/trigger pull and looks - far nicer than the stock frame + trigger.