Open carry has been legal in Ohio since 1803.
If there is no gunbuster sign posted, they should be friendly.
If some anti-gunner complains about you to management, expect management to ask you to cover, store or leave (cover it if you have a CHL, store it in your car and return, or just leave). If this happens, do not argue, just leave. (Occasionally, the manager will be on your side, but it's rare)
I recommend leaving (NOT completing your purchase), going somewhere more friendly to do your shopping, then calling the regional or district manager for the first store and letting them know what happened and how much you spent at their competitor. Offer to fax or email a copy of the receipt.