Doctronic's photo in Post #4 is of a BM caboose from the Great Northern collection, as are (I belive) the cabeeses in post #6. The BN caboose in Post #5 is a 24 footer from Norhern Pacific. Isn't this caboose exactly what a caboose should look like? excepting it should be mineral red with the N.P.'s Monad and have "Mainstreet of the Northwest" on it's side?
This one looks to have eather been sheeted in metal; or, sheathed with plywood, because as they came from the shops, they are sheathed in 2-3 inch vertical strips.
If this is a recent Walthers caboose it really is a Wabash issue (There is a detailing article in a recent Model Railroader about this very caboose). This caboose sorta looks like a Great Northern.