order online, if there's a longer wait than you want, you can still go check in stores, if you find one buy it and cancel the online order. I'm pretty sure your credit card isn't charged until your item is actually about to ship.
you can pick out a watch online, and check stock at local stores for pickup, before you have to commit to anything online.
Watches are a little different than phones, because of the many different combos due to color and size differences in both bands and cases.
so make sure to check other colors of bands, as it might be that particular band that's not available and not the watch body. unless you are set on having one color.
actually going into a store can help with this, as they will have a list of what they have, vs having to check item by item.
I don't know how the band selection is handled in store, if they're pre-packaged with watches, you might be able to swap them out before you leave,