Help!!!!

I took the instrument cluster out of my 83 D Turbo to install some LED lights, only one of the original bulbs was burning. When I began to put things together I found a problem with the main electrical connector, the round connector on the left of the cluster which must have a dozen or more wires leading to it. There was apparently a flat ended tab on the connector that slides into a slot in the cluster that ensures the plug is connected correctly to the instrument cluster. Well the tab is broken off, and there is no way to know how to attach the connector into the cluster correctly. All of the connectors are identical and spaced the same. Any suggestions?