Help with 1940 Mauser Banner Commercial

[Lugers down under]

I need some help please.
On Friday I looked at a Mauser Banner Luger which is comming up for sale and I need some help with a few things.

The Luger, I believe is a 1940 Commercial Mauser Banner.
It has a two digit (40) over the chamber. The toggle is the Mauser Banner.

It has an E/N proof on the LH side of the chamber above the number.
There are no proofs or stamps on the RH side chamber. The toggle has an E/N on the LH side first toggle section. The number is 7632W . However the barrel, which is 9mm and 4" long has no numbers or proofs whatso ever. Would that be correct? The sear has not been drilled.

I have studied Jan C Stills book on the subject and note that the serial number is in the correct range and not too far removed from the Swedish contract. I suspect that this gun may have come out of Sweden and has been re-barrelled in 9mm.
Any ideas would be gratefully appreciated.
Murray