Need help with 7 1/4 rear drain plug

Thanks RedFish & cudamark. Didn't want to deal with shipping on gasket for cover since she needs to be ready for a road trip to mopar madness this weekend , or just using silicone but my local NAPA actually has one in stock, removing cover definately best way to get all of old fluid out & check condition. Pretty sure she has never been opened up plus it is a rare 7 1/4 sure grip. Thanks for the help.

Oldschoolcuda