Value is a subjective thing depending whether you are buying or selling and who knows with the current economy, what motivation soem sellers have. With the rarety of the GT5 cars I would be surprised if the reserve is below $65K.
This looks to be a fairly unmolested car, showing all the attributes expected of a later GT5 model (relocated handbrake, dash vents and raised console etc.) The only sure way to verify it's provenance as a GT5 is to get factory records. I believe there is a way to contact Claudia Lodi who was a De Tomaso employee and has access to records, maybe someone else has her e-mail address?
Good luck,
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.