The Shimano Lark is a Skylark with the cable clamp bolt mounted on a sprung ‘cable saver’ arm. I have always liked this feature as it gives a pleasant supple feel to the gear change.
I think this example is the third version with the name stamped into the outer parallelogram plate. The typeface used is pleasantly 1960’s with a strong reek of Cadillac (or even Schwinn).
This example is date stamped ‘P11’, which could mean ‘November 1970’, and so comes before my example of the first style of Shimano Lark, which is stamped ‘P12’. Maybe my understanding of these codes is wrong!