This is the only one of these I've ever seen: a Mark Twain ticket with the stub still attached.
If you look closely, you will see that it's stamped July 17, 1955. I don't have any direct evidence that this ticket was obtained on opening day, but I do have some circumstantial evidence. First, there's the very low serial number, but since I don't know the system by which serial numbers were printed on tickets or if ticket serial numbers were ever reprinted, I don't put much value in this information. More meaningful to me is that I have a complete railroad ticket that was incontrovertibly handed out on opening day, and that ticket is stamped on verso in the exact same way and in the exact same style. Its stub is also similarly hole-punched with a star.
Can anyone out there provide any additional information?