the set seen in my photo came with tiny screws. I've done both silicone them in place as well as put M3 screws in.
A good point to make about these scales - a problem that cropped its ugly head up today - if the glass scale gets wet, they stop working...
I've been running with a lot of coolant lately on the lathe, the X scale stopped working today. that means I have to take it apart and physically clean the glass. a rather large pain... Doesnt happen often, but does happen... always idiot check your work/numbers...