I see three different chips, the inlays are different sizes and colors.

From the David Spragg post: http://www.marlowcasinochips.com/links/davidspragg/borland/borlandfantasy.htm

77 Thunderbird $100.00 1948-1976 N5981 black 3 orange (5/8") 2000 2/23/92?
77a Thunderbird $100.00 1948-1976 N5981 black 3 orange (1/2") 2000 6/13/95?

Is there a 77b? How do I best tell a 5/8" from a 1/2" I know measure but seriously, I'm looking a bunch of these Borlands, and they are sometimes different widths and/or different thickness. The one in the center is the same color as the chip on the right.