Looking at the schematic you attached, the screws are actually item 5. They are to attach the door handle itself (item 7) to the door. They don't seem to be self tapping from the schemaitc, but the thread is listed M5x16. I called to double check with the dealer, and they confirmed the thread size. Actually, I called them this morning and the guy said he didn't have a thread size only a part number. When I called them after your post to see if he could confirm 100% the self tapping characteristic I got a different guy, and he confirmed the size without me giving it to him first.
Even though I'm confident I need the tap, I'll pick up some self tapping M5 screws along with a tap while I'm at the parts store today just in case. I can always return the tap if I end up not needing it for the install. I haven't needed an M5 tap in the past 10 years so I doubt I'll need it anytime soon outside this project... If it turns out I didn't need the screws, I'll put them in an empty harware bin on my shelf. I'll use them eventually.
