No need to worry about accidentally putting the 7.92 x 57 or 8mm Mauser in the Japanese rifle Wild Bill.
The rifle you showed in the photos is a Type 38 and is chambered in 6.5 x50 Arisaka. An 8mm will not begin to chamber in it if the rifle has not been altered since the War.
The top of the receiver below the circular chrysanthemum stamp will show three horizontal lines - three - and below them will be two curved vertical lines - eight -. And below the eight is the Japanese character for 'type'.