Yep, they would rather charge You for new curtains even if its not needed. A lot of the red curtains and even some K have been lost in such way.
Originally Posted by tjaded
Excercise the shutter a bit on all speeds, the slow ones might lag under 1/15..
If its with the original lubricants, then some excercising should help.
If the curtains are not stiff, then change is not needed. You might wanna bring it to local qualified technician to open the shell (6 screws) to check the curtains front and back, while You are there, it takes 2 minutes.
On mine, the slow speeds gear needed cleaning only once since 1940.
Good luck and have fun!