Steve, if you're not worried about the nonoriginal drivetrain I certainly wouldn't worry about a possible Tempest fender! The only difference between a Tempest and GTO fender is the location of some trim holes. If the holes were welded up no one will ever know.
I hope this one works out for you, if it doesn't I've still got that hardtop sittin' there

. It's a whole lot cheaper than those others that you were looking at

.
Good luck.
Jeremy
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1966 GTO
1969 Lemans Convertible- F.A.S.T. legal family cruiser. 12.59 on G70-14 Polyglas tires. 1.78 60'
1969 Bonneville Safari- cross country family cruiser. .
1979 Trans Am 400, 4-speed, 4 wheel disc.
View from the drivers seat racing down Atco Raceway-
http://www.youtube.com/watch?v=GhYDMdOEC7A
Ride along in the other lane-
http://www.youtube.com/watch?v=mIzgpLtF_uw