Based on your description it sounds like Rock auto has the pics mis-identified. The mount with two 3/8-24 attaching studs is for the Right side. The left is the one with a single 1/2-20 stud sticking out in opposite directions. If what you have matches the pic I sent, yes it will bolt right in to your Lancer with the proper rubber insulators. And yes, '62-'66 SL6 all use the same (pictured) brackets and the same rubber insulators.
