Apple's naming scheme is stupid, so it's understandable that you ask. Quicksilver and Gigabit Ethernet are names for two of the more recent G4 models. PCI Graphics and AGP Graphics are the two first models, so if you say that you have a Powermac G4 PCI Graphics, then that is your model description.
If you have newbie questions, the best thing you can do is to use first Google and then the search function on this forum before you ask them, to make sure they haven't been asked a hundred times before. Faster for you, easier on us - and if you can't find it, feel free to ask.