This is correct. This is standard business accounting, not something that Apple does.
Channel sales -- i.e., sales to wholesale -- are considered shipments when they leave the shipping dock. The wholesaler is the customer, not the consumer. If Jane Smith buys an iPhone from an AT&T store, she is AT&T's customer, not Apple's at least in terms of her hardware purchase.
Apple's carrier partners do not sell on consignment. They paid for and own their inventory, just like auto dealerships. That's why retail auto salespeople are so intent on selling you what they have in their lot and not special ordering a vehicle. It's their inventory.
However, iFan is likely incorrect about wholesaler/channel payment. Most likely someone like AT&T or B&H Photo orders pallets of iPhones without prepayment, Apple ships and the terms are 30-, 45-, or 60-days. Unlike direct-to-consumer sales, wholesale transactions work on credit because of a long-standing business relationship.
When you look at Apple's quarterly financials, there's always an accounts receivable line item. That number captures some of those channel accounts who have yet to pay.
There are zero consumers in that line item. Apple will not send a direct-to-consumer shipment without a valid payment, whether it be a credit card authorization, cash at a bricks-and-mortar store, whatever.