If you haven't run the engine it's fine. Just flush the clutch compartment out with mineral spirits. You can plug the drain hole with a little piece of wood or plastic, then add a quart of spirits, wobble around as much as you can for a minute and drain it. What little lube stays stuck will be absorbed in the dust and be covered by new dust.
Worst possible case is you find it's invaded the friction surfaces (shouldn't have, really, unless you pulled the clutch lever while the compartment was full) and you have to change the clutch, which is your only other option now anyway. Give it a shot.
BTW, the hole you're looking into is for timing the engine. There are flywheel marks to use with a timing light.