Don't know a USAF squadron named Grim Reapers but the USN one is VF-101, the F-14 training squadron. They have been based at NAS Oceana for eons, though in the 1950's were split between Key West and other places like Cecil Field.
Having seen the air wing of Ark Royal at Cecil it is not beyond the realm of possibility that one or more RAF a/c transited. However, had a close look at rescanned photo on the Community Webshots site and the Grim Reaper art doesn't look like any of the incarnations of the VF-101 Grim Reaper that I have ever seen.