Hello Kabul,

have a look at the attached, how the links were held in position varies for where the unit was serving and wheather it was an early, mid or late model. I think it was more a question of surviveability rather than a specific method of attachment.
For the late mid and late versions - particularly on the eastern front, crews welded hooks on the front plate for a more secure attachment, at service stops or in the field - although any NON STANDARD attachment to the hull was frowned upon as welding weakened the armour!! (- a catch 22 if a 152 is waiting around the next bend for you.)

Particularly with the early versions, strong wire was all that was used to hold the links in position, and as these links were not intended for actual use, the wiring up could be rather crude.

Hope this helps you out somewhat.

Rgds

John