The original pins tend to get lost and it so happens printing one is faster than purchasing replacements. The version with the smaller head is for when you still have the rubber seal around the pin, the other version is for when the rubber seal is also gone.

Edit the sources for different dimensions.

Printing

Printed with PETG and a lot (8 ?) of perimeters for strength.
Placed head down on the plate and printed without supports,
fan speed reduced to 10% to achieve higher shear strength.

The original sources are available at https://github.com/ceresek/prints/tree/main/things/repair-marimex-pin.