According to
swissmotor.ch the used Blitzes were F-60 S-01 and F-60-II BIW. I've got no clue what types they are. The Swiss army changed the front axle so that the steering angle was much shorter (8750mm to 10400mm), and the width was wider.
The original payload was 3 tonnes, but reduced to just 2 tonnes. The Blitzes were mainly used for towing the 10,5cm howitzers and as troop movers (2+15 seats), because the special designed
Saurer M4 was only available in small numbers.
They were out of service after 1966.