Good choice, Merrill.
The inner part of the handle is the most vulnerable part of the complete turn signal assembly and absolutely unique to the W113 column switches - which were made by VDO.
All the other column switches of this kind (108, 111, 114/115 and so on) are made by Kostal in Lüdenscheid...; the single parts are NOT interchangeable.
Unless you have someone 3D-printing this part (or that like), your old handle is usually "unrepairable".
So, best choice is to obtain another complete switch - e.g. from Oldtimer-Ersatzteile...
Yes, these are expensive - but at least available again.
Sorry to hear about your pain...
Best,
Achim