December 21st, 2011.
I concur with B3.3T, you guys really need to get to know the law a little better. If the truck was seconded down to the Sheriff's Department, very likely either the state surplus property officer or the State LE Property officer acquired the truck from Uncle Sam. The way that works is Uncle sells the affected agency the truck or other property for a paperwork fee, usually quite minimal. The requirement is that the acquiring agency hold the property, usually for two to three years, then they can dispose of it any way they want.
As military equipment it NEVER had a title, it was purchased by Uncle on a Government Purchase Contract, and equipment so purchased doesn't have a title as Uncle doesn't need a title, his powers in these matters exceeds the state jurisdiction. Likely the Sheriff never needed a title either as it was a government to government agency transfer of property, nothing more, nothing less. NOW if the OP has a legitimate bill of sale from the Sheriff with the SN and such data on it, there are probably only a few states anal enough to not recognize a Government bill of sale, so the title should go through no different then any other cop car sale.
As a footnote, a City I lived in once turned down for $300.00 paperwork fees a rebuilt GE 44 Ton Diesel Electric Switch engine (locomotive) form the USAF through State Surplus.... All the puppies had to do was hold it two years and sell, in the meantime my RR museum could have used it for a shop switcher, now the locomotive would be worth 30 or 40K$.... So set up a non-profit museum and you too can join the game.....
Have a Merry Christmas and a safe and prosperous (we hope) New Year's!