I was surprised to see that this program was still going on after 30 plus years. I had a '52 H back in the mid-1980's, and got a free cap for it at that time.
That tractor was sold in 1987. In 1994 I bought a rather rough '48 H that I have used off and on since. I went to CaseIH and filled out the form today to see if the '48 tractor has ever had the cap replaced. It has the new style cap, but it is seriously corroded. So many of the new caps were floating around back in the 80's, that it is possible that the one on the tractor now came from another.
Will see if the serial number pops up on the registry.
As a side note: On the form page for the new caps, it states that the program will now be extended indefinitely as there is such a low demand, and a high inventory of caps.