Large mark along bottom edge near left corner

Mark above slot

Double-mark in top left corner

a

Mark in bottom left corner

a

Mark in bottom left corner

a

Small mark + semicircular weak mark in top left corner

b

Weak mark in top left corner - no mark in top right corner

a

Small mark on bottom ridge right of center

a

Small marks between stud 1 and 3, and between 2 and 4

No mark on bottom ridge

Small marks between stud 1 and 3, and between 2 and 4

No mark on bottom ridge

Line at 10-o'clock of stud 4

Small mark near center on bottom ridge

a

Mark above slot on left ridge

a

No mark above slot on left ridge

Mark in bottom left corner

a

Mark in top right corner

a

No mark in top right corner

Double mark in bottom right corner

a

Marks above slot on right edge

a

a

Mark between stud 2 and 6

a

Mark between stud 2 and 6

a

Three marks between stud 2, 3, 6 and 7

a

Mark between studs 2, 3, 6 and 7

Pip 8mm wide

b

2mm recess on edges around center. Dot-pattern inside center ring. 6mm pip.

b