Owners of existing National Flood Insurance Act policies with respect to structures located within the Floodway established under section 
1600c of title 
43 shall have the right to renew and transfer such policies. Owners of existing structures located within said Floodway on October 8, 1986, who have not acquired National Flood Insurance Act policies shall have the right to acquire policies with respect to such structures for six months after the Secretary of the Interior files the Floodway maps required by section 
1600c
(b)(2)  of title 
43 and to renew and transfer such policies.