Many Glacier boat tour

This may be a dumb question, but I have a round trip boat reservation for Many Glacier at 2:00. From what I understand they take you across Swiftcurrent, a 0.2 mile hike then across Lake Josephine. Then you have the option to hike. It says “Choose between a 1.8-mile round trip walk to Grinnell Lake or challenge yourself with the 7.6-mile round trip hike to Grinnell Glacier.” Does the 7.6 mile take you to upper Grinnell and Grinnell Lake? I’d really like to be able to go to both. And if so, would I have time to do that and be back for the 5:45 return? This is our first visit to Glacier and I’m trying to check all the boxes. Thanks!!