R12 - Can iProcurement Punchout be implemented without implementing Inventory?

Hello,

Can iProcurement Punchout be implemented without implementing Inventory?  Can we set up Item Category in Purchasing even without implementing Inventory?

One of my clients does not have any Inventory PO's.  But they do want to use iProcurement Punchout for shopping office supplies. They plan to buy P2P (iProcurement, iSupplier, Purchasing ...)  modules but not Inventory module, as well as no Oracle Supplier Network. 

I knew Purchasing can be implemented without implementing Inventory Module.  Does any one see any concerns and issues for the modules this client plan to have?  And I am not 100% sure if we can create Item Category in Purchasing even without the Inventory module implemented.