Yes plastic (delrin/polypenco) pipes sound pretty much the same as wood pipes by the same maker.

I had Dunbar pipes in blackwood and poly and the tone of the bass drones was identical. The poly tenors were a tad brighter than the blackwood tenors but when I measured them I found that the ID specs were slightly different wood v plastic, which I account for the difference in tone.

AFAIK no other maker used the odd huge fat ivory mounts that Robertson used- they're one of the few makes that are easy to ID.