As far as I can tell, both have open cartridge forks.The 16 had cartridge forks. The 17 not.
FWIW, I've installed those and wrote some posts about it in this thread: Installing Andreani 105/KT7E fork inserts in a post-2017...I was looking at this on Ebay Andreani Fork Cartridge Kit for '17-'19 KTM 390 Through Bolt 105/KT7e 105/KT7 | eBay .. but I am taking a shot in the dark at best when it comes to forks and suspension internals.