A "Junk Title" auto is a Parts Only vehicle. Usually issued for heavily damaged vehicles. The issuance intends to inform that the vehicle is now deemed unsafe to be placed back into service even following an industry standard repair. You need to access your DMV website to determine exactly what that classification means or the DMV in the state the vehicle is located. In some states, a Parts Only vehicle is not sold with a rebuildable title or it has had its VIN numbers defaced or removed from the dash. It could also mean that the vehicle has been fully immersed in water. Never even consider a Flood Damaged titled vehicle except for parts, esp if you believe the immersion was salt water.
As already mentioned, the only way you can determine under what circumstances the vehicle was judged to be Parts Only, is to locate the Insurer or if the present owner of the vehicle has a copy of the Loss/Damage Report issued by the insurance company who last insured the vehicle and has now written it off as a loss. Sometimes the Loss/Damage Report will follow a vehicle through the salvage process.