you’ll probably get more answers if you post in Financial Aid and Scholarships - College Confidential Forums
However a quick search says the answer is maybe, the crucial factor seeming to be whether it adds up to more than the gap UC left you with. I’m not an expert, though, try the FA forum above
If all the aid you receive — outside scholarships, financial aid from your college, and government grants and loans — ends up being $300 or more above your calculated need, the federal government requires your college to reduce the amount of need-based financial aid it awards you.
It’s up to your college to decide what type of financial aid to reduce or cut if you receive an outside scholarship. Some cut down the college’s grant. Others may reduce the amount of your loan. That’s to your benefit — it means replacing loan dollars, which you must pay back, with scholarship dollars that you don’t pay back. Other colleges may apply your scholarship award toward the next semester.