Optics and open sight rail for Colt GCNM

Regarding the various configurations of the Series 70 Gold Cup,  I know that with the more recent years' production of this gun, they added and then dropped (and then added again...) the rib along the top.  I have one of these newly manufactured guns which includes this top rib.  I don't know if these current ribs exactly match all other versions when they were used by Colt.  Does anyone know whether a rail is currently manufactured that will nest down properly over top my rib and bear properly on the slide?  And better yet would be if that rail had a hole pattern that matched another Bo Mar type rib with integral sights, which is also currently available.
Thanks guys.

Check with Clark Custom Guns.  They make a mount that will fit the enhanced 5" Gold Cup.  You can ask them if it will fit your pistol.
https://clarkcustomguns.com/product/clark-custom-1911-scope-base/

Rock River makes a mount with sights, but I don't think it will work on your Gold Cup.
https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1683