Are you just transporting it to drop it off to the seller or you riding around with it? Will the case fit behind the seat?
You can have it in an enclosed case in the vehicle all you want, but I wouldn't leave it sitting propped on the front seat in plain sight unattended.
527.020 Carrying Concealed Deadly Weapon.
(8) A loaded or unloaded firearm or other deadly weapon shall not be deemed concealed on or about the person if it is located in any enclosed container, compartment, or storage space [regularly] installed as original equipment in a motor vehicle by its manufacturer, including but not limited to a glove compartment, center console, or seat pocket, regardless of whether said enclosed container, storage space, or compartment is locked, unlocked, or does not have a locking mechanism. No person or organization, public or private, shall prohibit a person from keeping a loaded or unloaded firearm or ammunition, or both, or other deadly weapon in a vehicle in accordance with the provisions of this subsection. Any attempt by a person or organization, public or private, to violate the provisions of this subsection may be the subject of an action for appropriate relief or for damages in a Circuit Court or District Court of competent jurisdiction. This subsection shall not apply to any person prohibited from possessing a firearm pursuant to KRS 527.040.