This pipe from WDC has an unusual flat, rectangular filter. Most filter pipes use a cylindrical filter.
I guess filters were good for something, back when all you could get was that gunky, syrupy drugstore stuff (yuck!). Pipe companies tried everything they could to cut down on tongue-bite and make the smoke "cooler and drier," when all they really needed to do was use some decent tobacco that wasn't pumped full of propylene glycol, sugar and artificial flavors.
I will admit that I started out on that junk. I think my first pouch was some Captain Black whiskey flavored. It smelled great in the pouch. Some cherry flavored stuff that I had once also smelled great in the pouch, and the same goes for some heavy black Cavendish that was flavored with black walnut.
Now, I would not object to them being used as sachets, but I wouldn't smoke them.
I have one old WDC pipe, a Wellington, which was their knock-off of the Peterson System pipe. It's probably my favorite pipe, although extra care must be taken when cleaning to make sure that reservoir isn't hiding any concentrated punk.