4.3 quarts. I would get it on ramps and drain it well , fill the new oil filter and put in 4 quarts. Back it off the ramps and with the car level check the stick and see how much more you need to add to get the stick to full.
I own a 2004 Impala SS 3.8 engine and 4.5 quarts of oil with the correct oil filter, takes it right to the full line...
My experience has been the same as Boss302fan. While things could differ across the various 3800 series and the particular vehicles they're in, 4.5 quarts was always the right amount for me in the past in my 90 Regal, 98 Grand Prix, and 99 Grand Prix.
Go back to OReily's and ask for an equivalent to a PF52...or you can tell them a filter for a '96 Chevy Impala, which will bring it up as well.
Unless it won't fit (it should), no good reason not to use the bigger filter.