Mod top/No mod top?
If that is all correct for the color combo I think it would absolutly be a 1 of 1. I seem to recall that the green floral pattern top was only availiable with the green exterior color. Having a Mod Top without the Mod interior is not to unusual.Again according to the registry there were only 16 GTS built with the Mod Top so I totally think you should install the Mod Top. What about changing the stripe from red to a green to go with the Mod Top matterial? Check out the green body on this Superbee.Also Laysons lists material.
http://www.laysons.com/catalog.cfm?&nGroupID=385&nModelID=33&nModelYear=1969&startrow=51