It comes with mounting screws.
Yes for different mounting also
Yes, mounting screws are included.
Thank you for your inquiry regarding this item from Prime-Line Products. This item comes with SMS #8x1-1/2" PHIL FLAT ZINC screws. You can contact the manufacturer directly with your questions regarding this item, or any other product manufactured by Prime-Line Products by calling their toll free number at (877) 649-9740, or by contacting them by email at info@primeline.net.
The right hand mounts may work on the left, bottom screw hole would not line up though so you may have to drill a new hole. There is no shipping fee if sent to your nearest Home Depot for pickup and you can return for refund if they don't work for you so your out no money for trying!
It appears the left hand operator is not active on this site, but you can view it at www.primeline.net by entering item no. R-7020 in the search bar. If this is the correct replacement part you need, you can have it special ordered at the Pro-Desk of your local Home Depot store. R-7020 = Left hand operator as viewed from inside looking out. R-7021 = Right hand operator as viewed from inside looking out.