I believe that ring in the 1st pic goes on the inside of the front drum but I'm not positive. Did you drive or press the wheel studs out of it per chance?
Theres some pics in this thread that show that ring on the inside of a front drum with the wheel studs installed.
This manual explains how to press the studs out.

In case you don't have one, this is a link to an On-line 48-51 shop manual.

Good luck
Dave