Attached some pictures of levers from a 1952 336A, 1979 Marlin 444S and a 2014 336BL. Note the slight differences where the lever engages the bolt between the older 336 levers and their significant differences with the 2014 Big Loop.
The lever from the 1952 336A
will cycle the bolt in my 1979 444S. The lever from the 2014 336BL
will not cycle the bolt in my 1979 444S.
FWIW, my 444S has the "leveler" on the carrier. Some do, some didn't. I don't know if that made a difference on the 2014 BL not cycling it. I also don't know what year the lever design was changed. Most pictures of aftermarket BL's that I've seen show the newer design.
I can't help with sight recommendations. All my lever rifles are scoped, my aged vision requires it. The 444S has a Leupold VX3 2.5-8x36 (thanks Hoytcanon) mounted on low height Talley one piece lightweights.
1952 336A, 1979 444S, 2014 336BL
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1952 336A, 1979 444S, 2014 336BL
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1952 336A, 1979 444S, 2014 336BL
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