Well as of yet I don't think GM believes truck engines are best served by high winding V6 engines. They have always produced overhead valve engines for truck use. And in the past over head valve engines produced more torque at low rpms.
Obviously Fords twin turboed overhead cam engine proves that average torque across a wide rpm range can be accomplished with a smaller V6.
Gm knows that nobody is going to want to rev their truck engine like one for Indy to pull a heavily laden truck .. but there maybe other things that can learned for production engines...thermal barrier coatings , anti friction coatings, material sciences..
I think it shows that they are learning new things, and can build a successful Indy engine in cooperation with another company, just like they are working with Ford on new transmission designs... Who Knows where it will all lead..