Yes, absolutely, Charlie! There was one bit of red in each B&W scene: I remember the wine glass. It seems to me there was also a red rose in a bedroom scene and a trickle of red blood on a woman's neck in another scene. Perhaps the most beautiful set I've ever seen for a straight play.
I directed a production of Ira Levin's DR. COOK'S GARDEN at the Apple Corps Theatre in about 1984. Since the play had originally been written as an episode of Playhouse 90 or one of those 1950s anthology shows and had a sort of TWILIGHT ZONE feel about it, I thought it would be cool to do it all in B&W.
It is VERY difficult, especially with the budget of a small off-Broadway theater. Some greys tend to "go blue" (i.e., look almost violet) while others "go green" (tend to look olive). Depending on the ambient lighting, it's not always easy to tell which you've got and we spent the entire rehearsal period returning set pieces and props to get our greys to match.
And then you add lights and the problem of colored gels.
All of which made the accomplishment of the DRACULA set even more impressive.