Cubs historical sleuthing: 1970s edition

I was sent three photos to sleuth by BCB reader Scott Holmgren. I’m going to show you the first two, both taken before the start of the game in question, describe the scene, then show you the third.

Here’s the full photo above, plus the second:

In the first photo, we see Bill Madlock walking toward the Cubs dugout with a bat in his hand. On the bullpen mound is Ray Burris. Presuming that’s the pitching coach shown, it’s Marv Grissom.