There is no difference between a 1st model, 2nd model, or third model '73, when working the action. They are all the same. The only difference you might feel in these models, would depend on the wear each gun has. When they were new, they all worked exactly the same. If I understand your problem correctly, it sounds like the lever won't fit flat against the bottom tang, without appling pressure? If this is the case, the lever is probably bent. It should fit tight against the bottom tang, one end to the other all along the length of the bow. This dosen't have anything to do with lever or carrier arm springs. Lever latch should hold it fine with just two or three turns. It's easy to fix, but unless you've done it before, you should probably take it to someone who has a good working knowledge of an original '73. These are wonderful guns and work flawlessly with little effort, unless they're worn out.