Items about this rifle:

1) C.C.Johnson started riflesmithing around 1933 in Thackery, Ohio
2) His name stamp was 2 lines: C.C. Johnson
                                              Thakery O
3) in late 1947 his shop was moved to Lawrenceville, Ohio and the Thackery
O line was ground off the stamp. 
4) Any CCJ rifle with his stamp will have a 5 digit number under the forend.
and the first two digits are the last two of the calendar year the work was done in.
5) these facts can date any  CCJ rifle work.

Therefore any CCJ work on this rifle cannot have been before late 1947 due to there being no Thakery O line on the barrel.