no drop items CANNOT be sold, but i to have noticed they can have a price tag on them. i've tried the same thing you are speaking of, but they will not sell
Successfully completed my field trip to pick up one of these for my lvl 21 bard. I stripped down to a couple throw away weapons (two Giant Snake Fangs) and one of each basic instrument for the attempt. As I'm a Half Elf, I used invisi song (Shauri's Sonorous Clouding) to get through Nektulos Forest. I used speed song (Selo's Accelerando/"Selo's")through Lava Storm w/o any problem. Got just inside Nagafen's Lair and did an /ooc to see if anyone was camping "priest" or "king" rooms. I got no response. However, I did notice a group right at the entrance pulling Kobolds to the front to take care of. To my surprise, about the third Kobold to get pulled by them turned out to be the priest. The pauldrons popped, and after a quick /tell to the party asking if I could loot, I was zoning back out after about only 5 minutes total spent in the dungeon.
These often over-looked shoulders are great for a Bard. With a healthy dose of AC and dex, as well as 15 mana [ handy for CC/Charm-Kiteing] they are commenly left to rot because they are not tradeable. You can often pick up a pair at a lower level by sitting at the zone [or hunting in the pool room for 34+] and asking the leader of the King Room [where they drop] if you may have them.