(a) General rule.--Where the seller has identified goods to the contract by or before shipment:
(1) His procurement of a negotiable bill of lading to his own order or otherwise reserves in him a security interest in the goods. His procurement of the bill to the order of a financing agency or of the buyer indicates in addition only the expectation of the seller of transferring that interest to the person named.
(2) A nonnegotiable bill of lading to himself or his nominee reserves possession of the goods as security, but except in a case of conditional delivery (section 2507(b)) a nonnegotiable bill of lading naming the buyer as consignee reserves no security interest even though the seller retains possession or control of the bill of lading.
(b) Shipment in violation of contract.--When shipment by the seller with reservation of a security interest is in violation of the contract for sale it constitutes an improper contract for transportation within section 2504 (relating to shipment by seller) but impairs neither the rights given to the buyer by shipment and identification of the goods to the contract nor the powers of the seller as a holder of a negotiable document of title.