There is an ATGAgentFulfillmentMenuInventoryPlugin in ATGAgentClient with these methods:

(void)getStoreInventoryInformationForSkuId:(NSString *)pSkuId success:(void (^) (NSArray *pStores))pSuccess error:(void (^)())pError;
(NSString *)cellTitle;

These plugins are displayed in the fulfillment menu on the Product Details Page (PDP).