W108 ignition tumbler service

[sixto]

Does anyone know the procedure to replace the tumbler in a W108/67 250S ignition switch? I have the assembly out of the car. I can't tell how the shiny cover comes off. It's stuck in position 1 and the key won't go in more than 3/4 of the way. I see a little radial hole in the slot that would only be visible in position 1.

The wrecking yard wants $120 for a replacement ignition assembly and I can't get to a locksmith until tomorrow. Hopefully the locksmith is old enough to know that model designators used to start with numbers. What's the good word on this?

Thanks,
Sixto
95 S420
87 300SDL