Originally Posted by Blossom
I'm going to say yes because every time Amazon's updates the default fonts they add more kern pairs.
I have kerned my Caecilia modified font and it does not change how the test is displayed in an AZW3 formatted book (with no publisher fonts - I ran it through calibre).
Below are two screenshots. The first is with no kerning set and the second is with manual kerning. In particular, I changed the "wr" and "ri" to have a kern value of 100 to see if it changed the word "wrinkled".
I have restarted my KPW so many times today playing with the modified Caecilia font.....