A clearance item i bought was damaged, but damage was not listed.

I’ve been collecting parts for my computer build for the last two years, and back in November I bought my motherboard. My MSI B-450 A Pro Max was on sale for $71 marked down from $89. It was on clearance due to someone returning it I presume. On the yellow label on the box, it said that the motherboard was complete and never stated any missing parts or damage. Just today, I finally got all the parts needed to finish the PC. I start the building process, but when it comes to putting in my CPU, something felt off when placing the CPU into the motherboard. After taking it out, I realized the last owner got thermal paste into the pin holes for the CPU. After many unsuccessful attempts at cleaning it, I realized I could not get the CPU in. It’s now the end of April, and Micro Centers return policy is 15 days for motherboards. After these many months, I never checked the motherboard as I wasn’t going to use it until I had all of my parts. Would they still accept it as a return even though it’s been so long? Sorry for the long paragraph, just trying to get this situation resolved. Thanks