I bought two 67/68 TA spoilers and neither were what I expected.
I got one from a well known firebird parts seller out of Florida, it was crap even after he assured me I would be impressed with it. It had a terrible finish on it which would have required serveral hours of prep to get ready for paint. And had the common bow in the middle they all seem to have. The ends were still shaped to fit 69 quarters and do not match up too good on 67-68's. It was made by some Firebird outfit out of Canada. I sold it for a major loss as the guy seemed unwilling to take it back.
The second one I bought was from The Parts Place. It had a very nice finish on it, it was really ready to paint when I got it. But it has the same shape and fit flaw of the first one.