I really doubt that card was ever manufactured in PCI-E format, though I'm not sure.
Try this: Go to the start menu, then run. Type in "dxdiag" (without the quotes) and run that. Go to the graphics tab, and see what it says under DirectDraw acceleration and Direct 3D acceleration. If it says AGP Texture Acceleration, then I would assume it is AGP (you never know these days
). That might not mean anything though; someone else may know for sure.
Or you could download that. Whatever you want.