I have a M1910 with claw mounts, but it is my understanding that these were not installed by Steyr.

Kuduae or Marblekonus may be able to provide more background here.

I do know that several styles of mounts were fitted to MS rifles and carbines by retailers and smiths worldwide over the years. The proper way to mount them would be to add a saddle with the dovetail cut into it, rather than to cut directly into the receiver as so many (including mine) were done.

The Dorleac on this page looks like a fine example:
web page

These look good:

German Claw Mount

More:
NitroExpress