Hallmarks run from Jan 1st and are changed to the next letter on the following Jan 1st.
Sleepy was correct in saying 1934, the letter K would have been in use from the 1st Jan 1934 through to 1st Jan 1935.
As these medals were to commerate the silver jubilee in 1935 they would have had to have been assayed in 1934 to carry that mark.
They are good honest coins that have seen plenty of action over their lifetime. You could enjoy speculating about whose hands they passed through, and what items they were exchanged for.
Rust spots on the knee make this a KH4 rather than a KH2. Given this came out of Baldwin's basement, which Peck had access to when compiling his tome, I suspect he must have missed a few.