These are super tough items for the Dallas Cowboys collector. Beckett lists these as 1979, but the copyright date is 1980 stamped on each box. I have contacted Beckett Publications about this error, and they may have the correction in the next annual issue.
These are the last official card of each one of these players before the big card boom that started in 1990. I sent a set into PSA for grading a couple months ago so you can check the online guide to see them listed.
I have a set of boxes and a set of rough-cut cards available to sell or trade. Please visit my website for a closer look at these boxes and cards. Link provided at the bottom of this post.
Roger Staubach, Don Meredith, Bob Lilly, Chuck Howley, Don Perkins, and Walt Garrison.
1980 Cowboys McD's Super Boxes