Even back then in the mid to late '90s, I rarely bought animals from anyone. Main reasons are that there were (and are) too many people dumping unhealthy animals on the public, and I am have become more distrustful of people in general about they relationship with the truth. But when I did, I always asked about the ancestry in relation to "purity". And yes, there were some occasions where I asked, and having doubts about the answer, checked with other people. Sometimes I just walked away from the offering Sometimes I bought animals and was obviously lied to by the seller, as after some time working with them, became convinced they were not what they were sold as, and got rid of them.
It only stands to reason that a different looking cornsnake that would catch my eye, would be "different" looking. So it is only prudent to ask what it is about that animal that makes it look that way. And it was not at all unusual for me to ask the same person the same question later on, to verify the information I thought I was told previously.
So as far as the Ultras are concerned, there is nothing I have seen in them in the years I have been working with them where I can conclude they must be hybrids. They are no different looking nor acting from what you would consider as mainstream corn snakes as are say Miami Phase from Okeetees, or Blizzards, Ambers, Upper Keys, Sunkisseds, etc., from any other group of cornsnakes.