Locking tuners for 1982 s500

I picked up a beautiful '82 S500. I'd like to put on locking tuners but don't want to drill any holes. Iare there any living tuners that match up with the existing screw holes?

Do they look like these?


Conical split shaft tuners, almost as good as locking tuners, in my opinion.
I've upgraded my Legacy with Schaller locking and accidentally my ASAT with Sperzel locking tuners. There's an advantage, but not that much that I would do it again.

You probably will have to widen the post holes too, if they are not already at 10mm diameter.

Close to that....haven't figured out how to upload a pic yet...
I probably won't do anything if it requires any modification....I consider this a semi- vintage piece.

Thanks.

If the tuners are like the ones in the picture, I am not aware of any drop in locking replacements.-- Darwin