I love red dots on shot guns

As for the mount
1 look at B-square .
2 If it is a vent rib there are mounts to put a red dot on the rib
3 If B- square don't have a mount ,contact Charles Daly and ask if they make a barrel with a mount for your gun
4 last choice other than leaving it the way it is ,is to have the top of the reciever drilled & taped and install a base