Gelbe Farbe an Muttern, welche Theorie ist richtig?

Als lernender Sachverständige möchte ich wissen welche Theorie richtig ist,
die eine die eine teilweise mechanische (1), oder die andere - aus eine officielle MB-brochure (2) - die eine ganz manuelle Verwendung unterstellt:

1.
Actually, there is a field of study know as "dotology" that is devoted
to analysis, recognition, and cataloging of the paint spots on Mercedes
(no joke).

Most of the paint spots were applied by the special torque wrenches used
by Factory inspectors; when the wrench reached the specified value for
that fitting, it squirted out some paint.

Other spots were put on springs, motor mounts, and other components, to
designate their value in shore hardness, etc.

The reason these marks are being studied is that when a car is restored
to 100 point condition, it is considered essential that it has the same
paint spots as it left the Factory with.

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2.