Welcome to OCDO!!
Before you contact corporate, why not take a moment to search thisforum. The corporate policy is already known and well researched. Just use the search tool at the top right.
Basically, WalMart follows the law of the state in which the store is located, with an exception for one region where a regional manager was given or usurped authority to ban OC or guns, I forget which.
You need to see it for yourself, though. Not take my word for it.