Section 2-512. (1) Where the contract requires payment before inspection non-conformity of the goods does not excuse the buyer from so making payment unless

(a) the non-conformity appears without inspection; or

(b) despite tender of the required documents the circumstances would justify injunction against honor under the provisions of subsection (b) of section 5-109.

(2) Payment pursuant to subsection (1) does not constitute an acceptance of the goods or impair the buyer's right to inspect or any of his remedies.