Unless your Pfaff is pickier than my Pfaff, then no, you don't have to get the brand-specific bobbins. You *do* have to make sure that the bobbins you get are flat sided, rather than the ergonomic curve. I'm still using bobbins that I stole from my mother, that she had been using in her Singer (a tank which is older than I am, and only needs to filter up to the top of the priority list for repairs to go back in service).
If you'd like, I could maybe swing by in the next couple of days and take a look, to confirm.