How many light bulbs in a '73 Dart dash-cluster?

Since I had only 1 bulb trying it's best to illuminate the lefthand corner of the speedometer I decided go ahead and try my luck at replacing all the bulbs with led lights with the cluster still in place.

While fumbling around on the back of the cluster I managed to locate 3 bulb-holders. Got 2 of them replaced and managed to remove a 3rd one just above the column, but in a very slick way managed to drop the holder somewhere between the columnbrackets, never to be found again.

I searched and looked at wiring diagram but it didn't show the dash lightning, so, how many lighting bulbs are there in the cluster, and further more, can they be reached and replaced with the cluster still mounted?