WHOA, cowboy! ! !
For 8,500 $mackaroos you should be demanding a transferrable title or other LEGAL paperwork in order to PROVE OWNERSHIP of your purchase. If the "seller" has not FIRST established HIS LEGITIMATE AUTHIRITY to "sell" this vehicle, then it is NOT his truck to offer "For Sale".
MAKE HIM first go through the process - if it is indeed "abandoned at storage" - to obtain a "mechanic's lien" of whatever other LEGAL assertion of "ADVERSE POSSESSION" (this is a LEGAL TERM) is applicable in Colorado in order for him to sell it to you.
Absent of successful execution by HIM to do this amounts to some degree of THEFT of the vehicle from the current LEGAL OWNER.
As mentioned, yes in Texas a Bonded Title "could be" a viable option to you. However, for the HUGE PRICE being asked for this vehicle you should be making this guy invest HIS time and effort in assuring the the truck REALLY BECOMES YOURS "for keeps".
(Disclaimer: I am NOT an attorney. Nor am I attempting to render professional legal advice or consultation. I AM merely a lay citizen expressing my personal opinions of hobby matters based upon my personal understanding of applicable laws of which I have become familiar.)