if it's the factory original bosch distributor cap, which lead is printed on to the top of the cap.
it's always 1-3-2-4, but it's also always inlet, exhaust, inlet, exhaust...
Diamond outlines for Inlet, circle for exhaust (on the cap)
Cylinder 1 is the one nearest the radiator, 4 nearest the firewall (but you knew that!!!)
If that doesn't help, photocopy the firing order out of the Gregory's Manual (242 i think, it's in my local library). It shows the distrbutor cap without leads. Helped me when George was running rough, so I thought one of the leads was on wrong.
If that doesn't help, i'll get the page for you and write it out (won't be till after easter)