I will definitely check for those markings. I am excited the gun is of WWII vintage and very happy you pointed out the potential lack of hammer block.
I can't tell you what a great and thorough reply that was. Thank you!
(Also, just to correct a typo from my original post, I had assumed that the instructions dated 1958 meant the gun was NEWER (not older) - the fact it did turn out older is sort of a happy coincidence.)