yes anything they buy will still be there is deleted from the ACP panel. If a user buys & stores a item too then you delete / disable that item from the ACP the user will still have that item there to redeem, so say you made 10 medal items and someone bought all 10, uses 1 then stores 9, if you choose to delete / disable that item the user will still have 9 of them in their myItems page ready to redeem or send, if it is from a 3rd party app like the medals will be, you just need to make sure the application itself is enabled