HI Woodman
It depends on the version. Boba ROTJ are more of an off white color and they are reverse images of each other. the flaps slant like this... \ /
One Esb, They are the same color as the flightsuit, the left pouch is a bit smaller than the right pouch, the left is square and the right is rectangular, and both flaps slant like this if you are looking at the costume / /
I must add that it is up for debate whether with ESB the left and right are different sizes. There are screen caps that definitely look different to me, but that is really up to the eye of the beholder. You know how the screen can change colors and the shadows, angles, etc....
It is good to find all of the screenpics, and ref pics that you can, just so you can be confident in your decision.
Cheers
Debbi