Witnesses have been added by the state. They're listed at the beginning of the discovery supplements. For instance, Sondra Osterman was added as a Category A witness in the 8th Supplement of September 19, 2012.
Thanks. I haven't paid much attention to the state's supplementals. I get them, I open them, I glance through them, but I don't study them, and I'm not even sure I have the complete collection. I also haven't studied compilations made by people who do take the time to review the filings, like Diwataman. So, I'm not a reliable source for the conclusion that the state hasn't named an expert in any supplemental.