I bought this old gun at LGS today. It's pretty rough, but to clean it up i took the screw off the side plate. It's actually a nut threaded inside to the stud on the hammer. How does the side plate come off?
Many small taps to the Grip Frame with a small plastic or wood Mallet, ( with Stocks removed, of course ) and, the Side Plate slowly walks up and out a little at a time till it can be lifted away...
Please post us some images of the old 'DA' so we can enjoy seeing it!
The Kunhausen manual I got many years ago told me to use a wood small hammer handle. I have a 2 oz ballpeen and the handle is what I have been using for the past 35+ years.