Schwa, couple things to think about. My dad used an old Pachmayr flip mount on his Marlin 336 for quite a long time with great satisfaction. However, eventually it lost its ability to hold zero, often moving a few feet between shots. The same scope in a weaver mount tightened things up a lot, so it was the mount at fault.
I respectfully submit that a 4-12x is a bit much for a lever action. You can get all the magnification you need from a typical lever action with the 4x scope. While you don't mention the caliber, either of the most common 336 calibers limit out at about 200, or even closer for most shooters. At that range on deer, 4x is plenty.
As far as needing the scope out of the way for closer shots, if the scope is mounted correctly, you should have no issue with a 4x even at bayonet range. If the deer is that close, you won't likely have time to flip the scope out of the way and not be seen.
Based on a lot of experience, find a fixed 2.5x,3x,4x, or 1-4x variable, mount it low, and practice with your gun in field positions. It should work much better for you than a 4-12 on a flip mount. Just my recommendation, do with it what you will.
Old70.
