Exactly! There is NO WAY to make out what model car from the 8 digit number stamped in the trunk rail or rad support without other supporting docs. I may be mistaken, someone that worked high up in LE at one time told me there is a database with the SO numbers in it.
If it has a complete vin, it's a dirty deal. If the stamped numbers match your vin, it's a dirty deal.
Hope it works out for you, most of the buzzkill in this thread is spot on to question authenticity.