If they are little, plastic jam cleats with what looks like parachute cord cleated in them, then yes, those are leach line and foot line adjusters.
You can tighten them or loosen them as needed to prevent a "helicopter effect" when sailing. (sounds like a flapping noise) Also good for preventing the leach and foot from fraying like the end of a flag.
S/V Old Shoes
1973 Pearson 30 #255