I use fresh squeezed key limes all the time, and never have used the bottled juice but the recipe can use either they say no dfference in taste. I get my key limes for free so no need to buy the bottled. As far as I know regular limes are less tart than key limes and a different color as well, no reason you culdn't use regular limes the pie will have a little different taste but still yummy.
LuAnn