what mount are you trying to pick up?
try this:
Code:
local creatureName, spellID, icon, active, isUsable, sourceType, isFavorite, isFactionSpecific, faction, hideOnChar, isCollected, mountID = C_MountJournal.GetMountInfoByID(246)
PickupSpell(spellID or creatureName)
mountID 246 is the Azure Drake