Taxes on eBay personal sales

Hi Terry,
I sold approximately $1200 of personal items on eBay last year. Selling on eBay is not my hobby or business, I sold items I found in the basement that I had owned for 40+ years. I received a 1099-K form from eBay and the tax return instructions say that I must pay tax on the profits. Included in the sales was a rare 45 record that I sold for $600, I probably paid no more than $5 for it in 1979, and an old Nintendo game, I don’t have original receipts. Do I really need to include the details of my sales on my tax return? Please let me know your advice, thank you.