Sheridan Model-A - Super Grade.
With thanks to UJ for these pics of this very early Super-Grade.
See UJ's gallery here for more on this model:
And of this late model, serial no. 03427.
And of this very early rifle serial no, 160:
Sheridan Super Grade collection
With thanks to James for this pic.
Sheridan Model-A Super Grade collection
With thanks to Mark for these pics of 3 X model A and 1 X model B: