Even courses from much later can yield a few surprises. Here's two from the construction of Kingsbarns in 1998-9.
The land where the new course was built, and the existing nine hole course, was confiscated by the British government during WW II because it presented a potential landing site for a German invasion. They set-up barbed wire, fencing, cement blocks and laid land mines throughout.
After the war everything was cleared out, or so they thought. When construction was underway, a tracot ran over an unexploded mine, blowing it up and scaring the hell out of the operator.
Down by where the 16th tee is located, a road meanders down to the Ness. During construction they found a bone and called in a local archeaologist. What they had discovered was an intact skeleton of a young lady in a small coffen or 'cist' made of large flat stones. What astounded everyone was to learning that she had lived some 500 years before Jesus and was a near perfect example of someone from the "bronze age."
Both skeleton and cist were sent to the Glasgow University for forensic archaeological examination. To this day there isn’t a stone or marker of any kind to show where she was laid to rest.
Finally, when plans were made for the 18th green, it was decided that a small burn should be directly in front of it and that a bridge would be built right of the green. When they began to excavate for the watercourse, they were stunned to find that there was actually an ancient man-made watercourse, a 'condie' complete with stonework and cover running exactly where they were digging and running exactly where they wanted to go.
Further up the course they then unearthed the remains of an old stone bridge that had been built by the Romans. Both were restored and sit on the exact locations where they would have built new.