I have a 1993 HP commercial-marked (Browning Arms Company Morgan, Utah & Montreal P.Q. s/n 245NX5077*) and trying to find out if I have the Cast or the earlier Forged Frame. Mine does not have any grooves in the bottom (which would indicate a Forged frame).The earliest cast frames (circa mid-1993) do not have the "grooves" milled into the base of the magazine-well. I own a few and have seen many other cast-framed, commercial-marked (Browning Arms Co. Morgan Utah) Hi-Power's in both 9mm and .40 S&W that can only be identified by removing the slide and looking for the casting mark, no grooves at all. All FN-manufactured and dated (slide,barrel and frame) sometime in 1993.
Just from memory, all of these groove-less, cast 9mm frames still have the "long" rear slide rails carried over from the forged frames, deleted shortly afterward, probably in very late 1993. Just a rough estimate. Good luck.
Here is an example, I don't know what the serial number is.Would it be possible for you to tell me what the casting marks would look like and a description of what the "long" rails would look like? But even if it has the "long" rails and no grooves, that would suggest to me that it was indeed a Forged frame unless casting marks could be identified.