They are probably 255 stone hanging lanterns that were obtained by a bug long ago. At one time things would spawn in player placed boxes left in shops, just like the normal shop items spawn in shop containers.. this produced 255 stone statues (Sculptor's guild in Moonglow), lanterns (Inns), stretched hides (Tanners), grasses (Stables).. etc.
All the items were stuck in the boxes, but if a player chopped the box with an axe it would drop the item permanently to the ground where the player was standing. Sometimes these items trapped in boxes can still be found in IDOCs, or bought from collectors who saved them. If the lanterns you're seeing are called "hanging lanterns" then that was the source.
There's also Hemisphere's museum which if I remember had some doom-style lamp posts out front.. I think a gift from GM's maybe.. and then there's the old Seer-blessed places in Felucca, which might have all sorts of things outside them.