Thanks for the quick replies!
A biker friend of mine also mentioned Velcro, so that's 3 votes for Velcro and zero for a plastic pocket.
I got some 2" x 4" black Velcro strips to match the black leather.
I will cut down the strip to 2" x 3" because most patches are about 3".
My question is, should I sew the plastic or cloth part of the Velcro on the vest?
I was assuming the cloth part, what does everyone think?
Thanks again for all of the help!