That is the old method, which you have discovered does not work. CLEU's payload is returned from
CombatLogGetCurrentEventInfo().
The core problem you will face is that WoWWiki is ancient and should not be used. Use wow.gampedia.com instead, or redirect from wowpedia.org. Be aware that the payload is different depending on subevents; that much hasn't changed in some time with the
HUGE caveats that spellID and threat information do not exist in Classic.
https://wow.gamepedia.com/COMBAT_LOG_EVENT
I haven't tested for myself, but I suspect that spellID's "value" in Classic will be nil but it still exists in the return chain, ie:
Code:
local something, spellID, somethingElse = blah
print(spellID) --> nil