It should work like this:
-First opportunity to take a rug is in the sleeping goblins' barracks. If you take it here, a rug won't appear in the screen with the trinicorn corpse.
-Second opportunity to take a rug is in the screen with the trinicorn corpse. it will only be visible here if you missed the one in the barracks.
-But if you have the [spoiler]animal hide purchased from Taben the meat seller[/spoiler] then neither of the rugs may appear, and you'd need to us that on the spiked fence instead.
-First opportunity to take a rug is in the sleeping goblins' barracks. If you take it here, a rug won't appear in the screen with the trinicorn corpse.
-Second opportunity to take a rug is in the screen with the trinicorn corpse. it will only be visible here if you missed the one in the barracks.
-But if you have the [spoiler]animal hide purchased from Taben the meat seller[/spoiler] then neither of the rugs may appear, and you'd need to us that on the spiked fence instead.