Weird thought. Can the PCs buy supplies in the Boneyard version of Roslar's Coffer? I'm kind of leaning towards "yes". The town wouldn't have anything exciting.. as a mock up, it would have generic versions of everything.
But if you wanted to get anything off the basic list of items (rope, spikes, backpack, bedrolls, etc..) I'd allow it unless someone has a good reason not to. Indeed, it could be part of how they realize they are dead (Where is that potion of healing? It was on the shelf yesterday. Come to think of it, why is my ledger empty?).