If there's a convention i'll probably get it backwards but it's probably marking the low spot with regards to runout i.e. as round as the wheel may be it won't be perfect. Sometimes there's a dimple on the rim instead of a sticker.
Tyres often have similar marks on them, usually a red dot for runout and yellow for the light spot IIRC. They don't always have them but when there's a choice the tyre fitter is supposed to pay attention (yeah, right!) to the red one. This'd be aligned with the mark on the rim or with the valve if the wheel isn't marked. The yellow spot would normally be aligned with the valve
Unless I missed it tode's links are all for tyre markings?
I find the idea of using a stick on dot to mark something as permanent as a weight/dimension deviation a bit temporary? First good rain and competent valet and that dot is history.
I think I'd go with the QA suggestion. IIRC my AMG wheels from Germany had black dots on each rim, until I removed them prior to waxing!
The article mentions using dimples or stamps, not a sticky dot? Or have I missed it again?
Maybe a quick visit to Specsavers ?
"OE tire suppliers are required to
mark a tire’s radial runout high point
and OE wheel makers are required to
mark a wheel’s radial runout low point
This makes it easy for the OEMs to
match-mount tires to wheels from a ra
dial force variation standpoint during
production. In some cases, these mark
are made with paint dots that help ser
vice technicians remount tires down the
road. However, sometimes these mark
are made using temporary stickers
which either fall off or are removed af
ter mounting. This leaves no readily vis
ible reference marks for the tire techni
cian for future service."
Like my reply then in post 6
Like hotrodder's reply in post #5