Does it have a built in rear sight like regular carry handles or do you need a red dot with the rear sight built into it? — 1 Answer

It is clearly just a handle for a rear mounted red dot. If you're looking to do some sort of backup irons you can either go to offset irons or have a dot that has the backup iron built into the deck and have the deck height high enough to work with a front site. No windage adjustment, but your front site is adjustable for elevation.

Can't imagine you're using this for anything but a PCC or something for close quarters work where the irons wouldn't have to be perfect as backup.

If you're looking to do a dot with backup irons, you're better off going the standard carry handle route, the Next Level or KE Arms t1/t2 mount and a rifle dot of your choice.