Howdy and welcome!
IF that steering column is similar to the one in my '70 Monaco and '80 Newport, it is a Saginaw column, which means it shares many architectural situations with GM steering columns, although it was built to Chrysler's specs.
The item you desire generally was not available to the general public, although some do appear on eBay and such every so often. BUT you can get something very similar to it from aftermarket tool sources. But, then too, you might not need it, but having something like it can be easier and quicker to use that what I did, which was use my feet to compress the spring behind the lock plate, so that the circular wire clip could be removed (or installed). When I did that in the middle 1970s, I was younger, more limber, AND leaner, so it worked.
So, check with your local auto supply (usually in the Lisle brand) for a "lock plate compressor". Perhaps they might have one they could loan you rather than buying one?
Just curious, what sort of issue might you be having that you need to remove the lock plate?
Just some thoughts,
CBODY67