I don't have an answer, but I can help you find one.
It's going to cost you some to get your answer, but this is potentially a very valuable gun.
Contact the Buffalo Bill Cody Museum, they house the Archives of Winchester.
Give them the model and serial number and they can give you documentation on the gun.
Check that the gun matches the description, (caliber, barrel length, grip, lever, sights)
It may be that somebody at the plant pulled the receiver out of the trash and re-barreled it.
Most experimental guns were made for testing and they would have been pulled apart and checked for stress and durability after heavy use. If it was actually marked destroyed, it's probably because they ran tests that would have made the gun unsafe for further use.
They would do things like put triple the mount of powder into a round and then fire it.
If the description of the gun matches, start looking on line at the major auction houses that handle firearms, they will be able to give you a certified appraisal that you can use for insurance purposes and it will give you a place to start the bidding.
If it's what you believe it to be, it will be a hot item.
Receiver
On the receiver
It means that it is a Model 1890 (90) receiver. When Winchester introduced the Model 1906, they used the exact same receiver and action as the Model 1890, with exeption of the cartridge carrier. To readily differentiate between the two, Winchester stamped an "A" on the Model 1890 receiver and a "B" on the Model 1906 receiver. Bert H.
Receiver/barrel
Look at the receiver
Receiver
Check the receiver and barrel
Receiver.
Check the receiver.
Receiver.
barrel, tang, receiver
Check the receiver and barrel area.