(1) Where the contract requires payment before inspection nonconformity of the goods does not excuse the buyer from so making payment unless:
(a) The nonconformity appears without inspection; or
(b) Despite tender of the required documents the circumstances would justify injunction against honor under this chapter (section 5-109(b)).
(2) Payment pursuant to subsection (1) does not constitute an acceptance of goods or impair the buyer's right to inspect or any of his remedies.