For a visual the different variations are:
1 - 1st Name Not Outlined
2 - 1st Name Outline in White
3 - Batting, Pinstripes
4 - Portrait
I'm just an exhibit collector not scholar, but in my experience variations 2 and 3 are common, variation 1 is uncommon compared to 2 and 3, and variation 4 is rare. The first three can be had for $25-$250 depending on condition/back. The portrait doesn't come up often and it's probably a minimum $800-$1000 in low grade.
If you wanted to get technical, however, there are probably dozens of variations of the Mantle exhibit all things considered. They include blank backs, post card backs, and stat backs, B&W, "Printed in USA" vs "Made in USA", and location of the printing designation. ESCO printed new batches of the cards yearly and made small modifications often. Maybe a Mantle or exhibit collector can chime in and give a full checklist, but I know they can be found with post card backs, black stat backs, blue stat backs, and red stat backs. Just a guess, because I don't even know if the portrait was printed in 1962, but I'd imagine a 62 Portrait Exhibit with a red stat back would be the rarest of the rare.
