The number on the inside back of the helmet skirt is the manufacturing batch number. There there is some surface rust on the shell but there are are no dents nor holes in the shell so you will honestly like this shell.
The helmet you see in the pictures is the actual one you will be sent and it looks better in real life than on the pictures. The item "Czech civil reissue German army original WW2 M35 helmet shell size ET68 inv#637" is in sale since Tuesday, March 19, 2019. This item is in the category "Collectibles\Militaria\WW II (1939-45)\Original Period Items\Other WWII Original Items". The seller is "vit-zemanek" and is located in Czech Republic , EUROPE. This item can be shipped worldwide.