Perak is on the west coast and was one of the first states to come under British influence. The states the grandparent mention are on the east coast and tend to be developmentally uh at an earlier stage.
Definitely going to agree with that “uh” but things in the 60s and 70s were really different.
My mother grew up in Perak (40s and 50s) and I just asked her about this and she said she doesn't particularly remember seeing Jawi (she was from a different community). Of course all those pre-independence documents like my parents' wedding license are in English!
I don't remember it much from various 60s/70s visits as a kid and it's the kind of thing I used to looked out for. Times have changed!