NO. 1980 quarters are not silver.
All U.S. quarters dated 1964 and earlier are silver.
25¢ All quarters dated 1965 and later are made of a "sandwich" of copper and nickel. If it looks like silver it's been plated.
A quarter is made of 91.67% copper and 8.33% nickel. However, before 1965 quarters were made of silver.
1964 was the last year US quarters were made of Silver.
All circulating quarters dated 1965 and later are made of copper-nickel, not silver.
US quarters were not made of silver in 1965, but rather of copper-nickel. The last silver quarter made for circulation in the US were produced in 1964.
They were made from the very first quarters till 1964 being the last year.
Modern silver quarters are only made for sale in special "Prestige" proof sets sold to collectors. They're made of the same 90% silver / 10% copper alloy that was used for circulating quarters before 1965. Circulating quarters dated 1965 and later are made of nickel and copper, and do not contain any silver.
None of the coins made for general circulation have any silver. Only the U.S. San Francisco Mint struck any silver bicentennial quarters and that's just 40% silver. But not all S mintmarked coins are silver. They issued proof and uncirculated 40% silver coins and proof clad coins with S mintmarks.
All quarters from 1796 to 1964 are silver and 1965 to date are copper-nickel
1932-1964 Washington quarters were made of 90% silver and 10% copper. All circulating quarters dated 1965 and later are copper-nickel. Special 40% silver quarters were made for collectors in 1976 and since 1992, 90% silver ones have been made for Prestige proof sets.
All circulating quarters dated 1965 and later are made of copper-nickel, not silver.