I believe that the GT/CS aka 1968 California Special, was inspired from that car. Yup, I'm pretty sure.
Yes it was. Lee Iaccoca was in LA for a dealer meeting in '67. Several dealers approached him with the idea of a California only promotional car that would get people into showrooms. They came up with this idea because the intro of the Camaro and Firebird in 1967, understandably had cut into Mustang sales. California had accounted for 25% of all '65-'66 Mustang sales so these guys carried a big stick.
Anyway, they had Little Red parked in back of the hotel where the meeting was taking place and showed it to him. A dressed up coupe with the Shelby styling cues. The goal was not to build and sell a lot of GT/CS cars. The cars would be used to build a very large advertising campaign around to drive traffic to the showrooms where hopefully, they could sell a Mustang (GT/CS or not) or even some other Ford product. Iaccoca thought it was a great idea and took it back to Dearborn where the GT/CS became a reality