remove the
right grip first, using your finger from inside of the magazine well.
Then carefully remove the
left one. Be careful not to crack or chip it near the safety lever.
Glad to hear the small part is numbered "91" and just doesn't show up well in the photo.
That happens a lot.
While the grips are off, you can go over the entire gun with a light gun oil. That should be enough to clean off any left over gum, grease or old oil.
BALLISTOL is an excellent cleaning and preservative product that works well for the pistol and grips.
If you are only going to own one Luger, this would be the model to have.
It is iconic and was only produced for a few years before an during WW-1.
The finish is nearly gone, but having all matching parts is much more important.
This is the same make and model luger that I first bought for my own small collection.