I saw this car on Milestone and concluded that someone made it. Nice quality and done long ago, possibly in the teens, but does not make sense as a Lionel factory prototype.
Assembly with so many screws is too labor-intensive, even for a 1-off prototype.
Link-pin couplers would relate to pre 1910, pre 1906 if made by Lionel and the coupling pockets look smaller than those that Lionel used on 2-7/8" equipment.
Also why would factory R&D hand-make a car-body with wooden floor when Lionel already had the #12 carbody since 1906.
Trucks are single hollow large eyelet, so are later than this car would have been made by Lionel R&D.
It still is a great looking early car, but does not justify the price of an nearly factory prototype.