Sec. 217. Identification of goods as goods to which a lease contract refers may be made at any time and in any manner explicitly agreed to by the parties. In the absence of explicit agreement, identification occurs:
(a) when the lease contract is made if the lease contract is for a lease of goods that are existing and identified;
(b) when the goods are shipped, marked, or otherwise designated by the lessor as goods to which the lease contract refers, if the lease contract is for a lease of goods that are not existing and identified; or
(c) when the young are conceived, if the lease contract is for a lease of unborn young of animals.