sorry - and to answer your question - there are no steel flat hood options for 67-68 barracuda. That I know of...
you will need to go fiberglass. there is a bolt-on version of the same hood listed above from aar. you can use it with window regulator springs since they are a lower tension.
http://www.aarqualityfiberglass.com/products/barracuda-flat-hood-1967-68-bolt