Once you have it stripped that far down it's only three more screw fasteners, the cluster plug, and a spring clip to the speedo cable. Be careful of the mounting tabs they get brittle with age.
The lamp sockets come out with 1/4 turn.
Take a soft paper-mate pink pearl pencil eraser and lightly rub the contacts on the cluster plug and the lamp socket terminals, if they look too dark, to remove corrosion. Don't rub the printed circuit you'll de-laminate the copper from the plastic.
Spray the plug and lamp socket with Caig Deoxit D5 and wipe em dry.
Don't hose the contacts on the printed circuit with Deoxit D5 it might not play well with the plastic. You may be able to use Deoxit D5 on them but you shouldn't just spray it on. Spray some on a cloth and wipe a tiny amount of it on the printed circuit somewhere non critical to check whether it makes the plastic do nasty things. If it seems safe use a Q-tip with Deoxit D5 to clean the copper contacts on the plastic and wipe it off ASAP.
You can plug the cluster in without putting it all the way back in the dash to test it.