You came off as being sarcastic. I felt insulted. I don't have much patience with this stuff because when it comes to guns everyone is an expert yet nobody has any experience. So I though you were just being prick.
Anyway, I contacted Mesa and they were telling that parts that I know aren't compatible with the receiver.
It's really a matter of convenience. It works good for the 500 and 870 but it's not an option for the classic nova. I could just figure something out.
I'm thinking. I could get a B-Square saddle, a tacStar or Mesa shell carrier and a rear sling plate. Find some extended screws and make some shims then bend snip and tap the sling plate. I may have to carve the back side of the shell carrier a little bit but that's no big deal. Once I get all fitted properly I can just attach all with the screws through the holes that the drift pins for the trigger guard go in.
Now I know everything I need to know. Even though we seem to have misunderstood each other I do appreciate the help.