I often go around the entire show before I buy a gun just to make sure that I don't spend too much of my cash on 1 item only to find out later that the purchase left me without enough money to be able to buy something else that I would like more. This usually works out well because when I come back, it gives me a chance to haggle with the vendor who still has the item unsold and isn't sure whether I will buy it or not without a better deal. However, you're right about when you come across an item that you know that you really want, not to pass it by or else it could be gone when you return.
Woulda', shoulda' coulda' happens to all of us at some point in time.
It must have been such a shock to see the same model as yours sitting on the table for sale that you didn't realize that opportunity was knocking! Oh well, look at the bright side, maybe it just wasn't as good of a gun as the one that you already have but its evil twin!
Don't despair, there's probably a better twin [or model] that you'll like even better just around the corner.
