Which pens are which?

Is there a way to tell, within a macro, which pens are from the preference file and which are from the file itself?

More detail:

We import files from Illustrator and come across such wonder pens such as "0.09-1". I would like to cycle through these, but skip the pens that are defined by the preference file. I would like, if at all possible, not to have to do checks to make sure that I'm not cycling through normal pens. Any ideas?