My girlfriend went in for a covid test today. Only

My girlfriend went in for a covid test today. Only because of lingering symptoms that could of been from Covid almost a year ago this month. We were both kind of sick early February last year but didn’t think much of it. I live in Washington State and we had the first case of Covid in the USA in January if you want to believe that was the first case. Most of us here in Washington think it was running around here for a few months before they even recorded that first case here. Maybe someday they can prove that it came months before but nobody knew what it was or tested for it.

My question is, will we be able to know if we had covid from a year ago? I am sure antibodies won’t be noticeable but are they still there and will they still show a year later in the blood test we did today?

Thanks in advance...