Huwg.
According to Grab the tuning forks are cheap. Well I live in Quebec Canada and my Yamaha 180 (1963)is presently in shop awaiting the arrival from Toronto for replacement forks because they have worn out and need replacement. The Cost is $65.00
I told the repair man that I thought this was a little expensive, but when he showed me the book I am very happy because vintage parts (tuning forks)are very expensive. Like $160.00 and up.
Good lluck.
Great guitar by the way.
Beer