Hello Shannon,
First off, and I should have done it sooner... Thank you for putting together this website and community, it's great!
I ran into this at Fort McKavett in December '08. The park host explained the changeover but on his own accord admitted me with my state park pass. I guess I had a genuine "huh?" expression. Wound up putting my would be admission green in the donation jar and enjoyed exploring the grounds for an afternoon.