In The Chrysalids, would the signs that hang around David's house be an example of foreshadowing?

It is in Chapter 2 that David describes to us the house in
which he lives and the signs that you refer to. The signs are placed in the biggest room
- the main living room of the family, and David comments on how it
appears:

The
nearest approach to decoration was a number of wooden panels with sayings, mostly from
Repentances, artistically burnt into them. The one of the left of the fireplace read:
ONLY THE IMAGE OF GOD IS MAN. The one on the right: KEEP PURE THE STOCK OF THE LORD. On
the opposite wall two more said: BLESSED IS THE NORM, and IN PURITY OUR SALVATION. The
largest was the one on the back wall, hung to face the door which led to the yard. It
reminded everyone who came in: WATCH THOU FOR THE
MUTANT!

I wouldn't necessary
argue that these signs are examples of foreshadowing, as they don't really predict any
particular events. What they do indicate is the kind of community that Waknuk is - one
that always has its eyes open for deviants or "mutants" and is determined to purge them
from the face of the earth. This, you could argue, foreshadows the zealous manner in
which the community punish Sally and Katherine and then hunt Rosalind, David and
Petra.