Technical Mallory Distributor Caps

Hi All,
Is there a difference between Mallory 4001 and 4004 distributor caps?

Thanks, Steve

 

wild guess from looking at old catalog pages, 4001 is the ***embly, 4004 is the main part of the cap (minus the top piece and the rubber gasket).

 

That makes sense, all of the caps I have say 4004. I have not found a rubber gasket anywhere however...

 

The part number for the gasket was 24902 long ago, probably 4902 later on?

 

https://www.ebay.com/itm/234580224467?