Absolutely mention it. Your demand letter should state:
"Under California Civil Code Section 1950.5, you were required to return my security deposit or provide an itemized statement within 21 days of my move-out date (April 10, 2025). As of today, 27 days have passed with no response.
I am entitled to the full return of my $2,400 deposit. Additionally, your failure to comply subjects you to statutory penalties of up to two times the deposit amount. If I do not receive the full $2,400 within 10 business days, I will file a claim in small claims court seeking the deposit plus the maximum statutory damages of $4,800.
This is my final notice before legal action."
Keep it professional but firm.