No, they are synonyms
Narrow is used in the contexts of narrow roads or streets or a narrow-minded person. I guess narrow is used more figuratively and thin is used in physical contexts (thin body type, thin hair, thin atmosphere)
Spaghetti is thin and narrow; apply the sauce wide and thick.
A thin narrow strip of wood is either a lath or a slat.
The opposite of narrow(thin) is wide.
thin
Some opposites of the word 'narrow' as an adjective are: wide, broad, or thick.Opposites as a verb are broaden or widen.
A needle.
Either hungry, empty or thin would be opposites for full
thin, small, bony
Slender
The word "thin" has numerous opposites: wide, thick, broad, fat, stout, hefty, and substantial; and the verbs thicken, widen, broaden, repopulate, replenish, compress, or concentrate.Conspicuously absent are antonyms that begin with the letter N. The closest might be natural for unthinned growth. Or the trivial "not thin."It is possible that this is asking for the synonym, not the antonym.(A close synonym is narrow.)
The word narrow implies long and thin, as does slender.