Adjusting handlebars on a 2017'RS

[jtopiso_imp]

Hi,

Maybe it's a stupid question, but there we go:

From the original set-up, can the handlebars be rotated axialy in their clamps, or is there some kind of notching so the original position can't be changed without drilling or machining of some kind?

I'd just like to try some minor adjustment, to see if I can get the bars slightly higher and closer to me. Just a bit...

Any advise?

Thanks!