It is very hard to date a older Hi Power of this era because FN used the same serial number for different contracts. Serial numbers will not tell you the age of the pistols. They often only represent the serial number range that the contract requested. Close up pics of all of the date code stamps and proof marks will help. Just from what I am seeing.
*N on the slide after the PV stamp is an inspectors mark. Henri Florkin 1927-1958
*G on the frame after the PV stamp is an inspectors mark. Josef Charlier 1927-1959
The barrel seems to have a *G as well as the Liege Proof.
It is of course a thumb print gun with a tangent sight. The tanget sight is a type 2 which you ca identify by the way it is fixed to the barrel and the gradations on the sight.
Does it have a slot in the back of the grip for a shoulder stock. The grips are aftermarket the original would have had French walnut wood grips. Are there any letters under the grips on the back of the stock? Specifically KL or EV?
It is hard to tell from the pics but the gun looks refinished. The parkerized finish looks to cover or fill in some of the pitting on the gun. One other thing that would help is what does the barrel cam look like? Is it rounded or squared? The squared cam was introduced in 1938 but this will not fully nail down the date. FN never through away parts. So there are round barrel cams in early waffen proofed guns.
Dating BHPs to quote my friend Sub-moa is often a bit of a WAG.