Well, I can get pieces, but not the whole puzzle. I think it's a plaque at the R&A commemorating Old Tom Morris, who won the first Open. But 326 wasn't his score, it was the highest winning score, by JH Taylor, in 1896. And his winning margin wasn't 17 strokes, since the highest winning margin was 11 strokes.

How about 326 meters to the next green. In the US the holes are ranked in difficulty from 1 to 18, so might this be the 17th most difficult hole on the course?