Well, I didn't think a little item like mentioning the 350 H.O. hood would generate such a debate, considering the original post was about Firebird 400's!
But it's all good, because it's all information, and we're all information hounds.
Diego, I have found evidence of both the flat hood and scooped hoods on 69 350 H.O.'s, so I will retract my earlier comment.
So now the question is, which is correct? I seem to recall a discussion a while back on either the FGF or PY site about this, and it was suggested that when the run of 69 Firebirds was extended (after March 1969), the 350 H.O's may have received the 400 style hood, perhaps to move hood inventory with the 1970's on the way, I'm not sure. As we know, the 1969 Firebird 400's didn't sell very well in 1969 (a little over 11,000) compared to over 18,000 400's in both 1967 and 1968. Only 5,127 1969 Firebird 350 H.O.'s were built. They did not use the hood tach nacelles that appeared in the brochure. As a sidenote, it was a 350 H.O. Firebird that Royal Pontiac actually ran into the low 12's back in 1969, and ran well under the NHRA index.