I've seen this car listed for sale on another website, so I've seen more pics. Here's my opinion:
1) Most 71 Barracuda convertibles that haven't even had body/interior work started are bringing 40K, which is what the asking price is for this car. This car has most of the body done already, I believe (haven't seen it in person so I can only go by the description). It already has gilled fenders, which is a major plus. Also, it has new seat covers already. You aren't going to find many 71's in this condition at this price.
2) This car has no drivetrain, so that is going to cost you. On the other hand, it gives you the freedom to do what you want (old 426 hemi, new 6.1 hemi, etc...) without feeling like you need to be tied to a matching numbers 318 car.
3) Not sure what the status of the grille and front valence/valence insert/turn signals is. If they aren't there that will run you about 4K.
Realistically, to finish this car you probably need to spend another 30-40K (body & paint 10K, drivetrain 5-15K, top/interior 4K, other components
). So the question is are you willing to spend 80K plus your time for a convertible clone? With the muscle market down, this is probably not a good investment right now. It may be 5 years from now, no one knows. If you don't care about it from the investment aspect and have the $$$, then do it.
Just remember, it is always cheaper to buy a finished car than it is to restore one, but if you restore one yourself you can build it exactly how you want it.