You're either missing the cable release socket or the PC flash sync socket. Find a similar shutter of the same size and rob parts from it.
To disassemble the shutter:
1. remove the lens cells by turning them counter clockwise (anti clockwise).
2. remove the screw from the time dial with the dial set to 1. Lift up the number plate carefully and note the position of the parts under it as you remove them.
3. Remove the screw on the trip lever and remove the lever.
4. Remove the 4 screws in the face plate then lift the face plate straight up. Remove the aperture scale if necessary.
Do not operate the shutter with the face plate removed. The Compound shutter is fairly simple if you have good mechanical skills. Disassemble as needed to access the missing part(s).
Reassembly is the reverse of disassembly.