I needed money back around 1990 and put it on a table at a gun show. A couple of guys from the "Gulf Breeze Pistol Parlor" looked at it a couple of times. After about an hour, they came back and bought it. They clearly thought it was unusual. I don't know if it really was or not.
that makes no sense to do at all. The barrel should've been ported too. Possibly an amateur hack job on both the barrel and slide, so the previous owner rebarreled it(or completely misunderstood the reason for porting and just ported the slide). either way it was not a factory option back then and no reputable gun shop would've donr it.
CC