Got it working, if anyone else is interested in using this bezel pack, I combined the bezel and crt overlays for each game into one image using gimp, exported that as mslug.png and then I made a .cfg file and named that mslug.cfg . Put both files in the opt/retropie/emulators/retroarch/overlays folder. Make sure you name both the .png and .cfg files the same for each game.
My cfg file looks like
overlays = 1
overlay0_overlay = mslug.png
overlay0_full_screen = true
overlay0_descs = 0