Brandon is correct, they were made as door stops, or book ends, as some people call them, and the man with the ladle is similar to the Iron Man statue Cub-Bud spoke of. They were made to commemorate the last pour at Louisville before the foundry closed. There are actually two different dates of the "last Pour" pieces, the other is dated in 1984 I believe, and will have a persons name on it. When the plant closed in 83, a small number of people continued to work in the foundry to complete a parts contract that IH had with someone else (they made castings and forgings for other companies, one being American Motors), and it is the name of one of thoses individuals that is found on the "real' last pour door stop/book ends. They were cast, in cast iron, for each of those individuals. You can also find the same thing with the Memphis Plant name on them. They were painted gold, like the 9-14-74 Cadet statue
Yes they are collectable, and yes there are many reproductions of them. Real ones sold in the $100 to $150 (each) range in this area a couple of years ago, not sure about now because I haven't looked for any. I had the measurements for a real one at one time but can no longer locate them. There are a number of reproductions, but I doubt if anyone knows how many of either one of the originals were made.
The Iron Man Cub-Bud spoke of was given the name "Six Million Dollar Man" by the employee's, because they joked about that is probably how much IH had invested in it, and the TV show of the same name probably had a little to do with it. That and the fact that Mr.Jones (a pattern maker) started with a store mannequin, and added to it when making the pattern for the mold.
Brandon.