Knowledgeable collectors will know the difference. And they lust after prewar HP's that don't have the Browning Arms rollmark. I don't believe Browning started importing the HP until sometime in the mid 1950's- so FN had about twenty years worth of HP that would have only carried the "Browning's patent" rollmark and not "Browning Arms Company". And these are certainly collectable.
Buy it and shoot it. It's not a Jennings or Hi Point so it will still be worth something in twenty years.
FN has always been the manufacturer of the Hi Power. Browning is only an importer for the North American market. All Brownings are FN's, not all FN's are Browning's.
I don't believe Browning has EVER manufactured any of their firearms, All were made in Belgium by FN, Japan by Miroku, or in the case of the Browning BDA .380 by Beretta.
Several years ago FN opened a US office (FN USA) to market directly to military and police. These Hi Powers were marked with the FN & FN USA rollmarks, not BROWNING (since Browning was not the importer).
FN apparently decided that competing with Browning (FN owns Browning) was not worthwhile, so they stopped marketing the HP through FN USA. FN USA sold their remaining stock to several dealers/distributors (most notably CDNN who sold many of the FN 9mm's and .40's for $399. They have sold out of the 9mm and only have the .40 in stock).