No -- because in that statement he is contradicting his previous statement that "in matters of importance one should defer to the writings of the apostles".
So which is it???
They cannot both be true unless he is saying that one should obey the priests in unimportant matters, but obey the scriptures in those places where it really matters.
But since the office of a "priest" for the New Testament is not found in any of those writings of the apostles, Irenaeus should have taken his own advice and deferred to the writings of the apostles before penning those words.
St. Irenaeus is only authoritative when he agrees with YOU.