Identify light and appropriate replacement

Light fixture corroded and water got into the housing, so need to replace the pool light. Having a hard time positively identifying the light and determining an appropriate replacement. The existing light has screws at 12:00 and 6:00 on the face. Unfortunately, the top screw snapped and i’m having a hard time getting teh last part of the screw out, and the bottom screw was a hexbolt, which I don’t think was OEM. The interior dimension of the niche is ~9", and the diameter from screw hole to screw hole is 10".

The pool is very old, and I’m leaning towards this light being a Hayward Starlite SP-540 Series, or an Anthony Pool Light, both of which are obsolete.

I’m thinking of getting the J&J ColorSplash XG 120V LED. Assuming I can screw in to the top, I’m not sure what I can do for the bottom as I don’t have the notch, just the bolt. Would the CMP light ring adapter work instead? The adapter mentions a ground screw being connected to the ground wire, but this is a wet niche and the only wiring I can see is what goes comes from the light and through the conduit, so do I just ignore the ground screw?

I know that it is ok if water gets into the conduit, since the junction box is high enough, but should I try and plug the entry into the conduit after I run the wire, or just leave as is? How would I plug it? I think I read about an underwater epoxy.

Thanks for the help.

Mark