for my cover, there's nothing need to be "aligned", the cover closed and locked snugly. Just with bare hand I can lift the cover so easily. Mostly likely the whole piece will fell off easily over a bump. Currently I'm tying a velcro strap over the downtube to strap it down just with a piece of mine.

UPDATE: Long Teng now blamed the excessive paint on the edge of the cover  and downtube that prevent the cover to be locked securely, want me to use a rasp to grind off the excessive paint on the edge along the cover and the downtube opening