LM, the only 8MM stamped with a swastika was the 8X56R.
No 8X57 or 8MM Mauser was ever so marked as I have been told and have read.
The spent cases have little value really but I would hold on to them anyway as who knows what will happen later.
"The right to bear arms should not be infringed upon if only to prevent tyranny in government". Thomas Jefferson, Constitutional debates