They look like they would be bitts for tying rigging. However this is a little strange place for them, as the bitts where the tops of the hull frames. The bitts would actually be on the coaming around the edge of the deck/hull. They could however be cleats for also tying off rigging.
From what I can figure out on my plans(typical Billing Boat plans, very cryptic!):
If you look at S4 at the pic you provided - it gives the part number 114. 2,8x5mm, which gives you an Obechi strip, which must be cut to the size on the 'scale' plan
I assume all the others S3, S7, S9 etc, is made of the same material.
Then on page 18 of the instructions, it gives the rigging line dimensions, which I assume must be connected somehow to the corresponding parts mention above.