Yes. The Son was not begotten from nothing, but from the Father's substance because if the Son of God proceeds from the Father out of nothing, He could not be properly and truly called the Son.
It was explained above (Q27, A2; Q33, AA2-3) that paternity, filiation and nativity really and truly exist in God.
The true Son of God is not from nothing; nor is He made, but begotten.
That certain creatures made by God out of nothing are called sons of God is to be taken in a metaphorical sense, according to a certain likeness of assimilation to Him Who is the true Son.
The Son of God is begotten of the substance of the Father, but not in the same way as man is born of man; for a part of the human substance in generation passes into the substance of the one begotten, whereas the divine nature cannot be parted.
The Father in begetting the Son does not transmit any part of His nature, but communicates His whole nature to Him, the distinction only of origin remaining.