Walter Matthau is not in Actor (1978)

Hullo, Last week I had the privilege of seeing this very rare TV movie, and Walter Matthau is definitely not in it. He's also not billed in the credits. I don't know why he's listed on IMDb since there's no mention of him in any contemporary reviews or ads either. The only information about him being in the movie comes from websites which regularly copy credits from IMDb. I tried removing him from the page, but my correction got rejected ( #250929-163217-230000 ). Since the film's not online, I don't really know how to further strengthen my case. On the other hand, if anyone can show that he is in the movie, I'd be quite surprised. That credit really should be removed.