AIRSPACE: CLASS D svc 1 Jun thru 30 Sep 1300–0300Z, 1 Oct thru 31 May 1400–0200Z other times CLASS G.
... but the Grand Canyon VFR chart here says:
See NOTAMs/Directory for Class D/E (sfc) eff hrs
The VFR sectional just shows a class D ring around the airport with a class E surface area extension to the southwest:
When the tower is not occupied, how is the airspace around KGCN arranged?