Originally Posted by echinosum

Probably. But they've probably been open pollinated, so may have crossed with something else, possibly even a chilli pepper, so you don't know what will grow from it. Or it could be an F1 hybrid that won't breed true. Also it's probably greenhouse grown, so may not be the easiest type for home growing, even if it is a true seed of the variety.

So you'd do much better to buy seeds from someone who has carefully pollinated the plant for seed production, so you know what you are growing. Also choose a variety which is suited to small scale home growing without needing specialist conditions agriculturalists can given them. And comes with instructions specific to that variety. Specialist on-line sellers of pepper seeds are more reliable than picking up seeds in the local shop for things like peppers, and won't cost any more. I particularly recommend the Real Seed Company.

Green (also blackish or purplish) peppers are un(der)ripe red peppers, though some sweet peppers ripen to yellow or orange instead.