Make sure that you pick a pair that's unlikely to have ever been used, like the white/slate pair. There's always a chance that someone may have cut a pair over the years at a jack location. I think you will find that the white/slate pair will test continuous back to the protector.
The general prewiring concept (with any type of wire) was to keep the runs in the attic and drop down so that they were accessible for future re-pulls. This even applied for outlets that were at a lower level. It wasn't uncommon for a prewire loop to dip all the way down from the attic to a basement outlet and then back up. You really didn't see a whole lot of this cable used in exposed basement areas due to concern over damage.
