Dear Dave:
You might want to look for a Lyman 56 LA as mentioned, which was the period sight for your Marlin 336.
They come up on Gunbroker and E-bay from time to time. The prices range from $125-$200.
Presently I have two, one for a Winchester 71/94/1895 and another mounted on my Marlin 39A. They were exceptionally well made, and are easily adjustable.
Sincerely,
Chris Bemis
