From what I can see in the pictures, both of them appear
to be originals, but I would have to see them to be sure. The painted one that you posted the picture of, seems to have one ,and maybe two bidders, that have been known to sell reproductions, so it must be a real one
The chrome one appears to be a real one by looking at the ears and the mark around the neck. That mark is from the way it was hung in the plateing tank I'm told, and all I have ever seen had that mark. All the chrome ones I've ever seen were the same size as known originals, I have never seen a chrome, cast iron, reproduction.
The bear should be 4" tall from the top of the base to the top of his head ( not to the top of his ears. The base should be 2-7/16" from front to back, 2" wide at the front or back, and 2-3/16" wide at the center where the mold line is. There can be some slight differences with these measurements, but if any are 1/8" or more smaller , I would be leary of that bear.
I don't aggressively buy them , but will if I find a good buy, and I am not bidding on either of the two you posted the link to. Yes, you can usually find them in the antique stores and malls here in Louisville, because the Louisville IH Plant is the only place they were made. Supposedly some bears are the first thing cast when the new foundry opened in 1949, The bear is for the Farmall Cub, because it was "a bear for work, but a cub in size"