I don't recall the guy's face after 40 years. I can say that he was likely in his mid-20s. If it had been Poe, however, I would think he would have been a celebrity at a Trek con, but I don't think the guy was on any panels.Was it this guy?
https://memory-alpha.fandom.com/wiki/Stephen_Edward_Poe
If so it was the 2nd model. And just learned that Poe was his real name, but Whitfield was his pen name - as in the writer of The Making of Star Trek became the owner of the 2nd AMT model. That is the fun of posting, always learning.