Well, what kind of spec-ops are you referring to? Intelligence gathering? Disinformation? Raids? Disruption of enemy slocs?
In my view, the coast watchers in the Pacific is a form of a spec-ops unit, primarily tasked with intelligence gathering. There mission was in today's terms, evade and report.
Another is disinformation, such as the well-documented ops to convince the Germans that the Allied landing wouldn't be in Normandy.
For disruption of SLOCs, the British had their LRRPs in North Africa.
Other spec-ops would be the insertion and recovery of personnel.
The activities of the US Navy's frogmen could also qualify as spec-op.
Would airborne operations qualify as spec-op? Looking at it in the context of World War II, it is but today, I think airborne is now considered as conventional.
Given your fresh idea, let's start with the coast watchers.
What if the coast watchers were absent when the Guadalcanal campaign began? Would the US have managed to hold on to the island without the coast watchers? I hope this jives with what you have in mind.