The size and weight are both the same of a normal quarter, so I am just unsure if it’s missing a clad layer on both sides or something entirely different. Thanks for any info you can share!
If it were missing both clad layers, it would be thinner, it would weigh less, and the strike would be weaker. Environmental damage can leach away the nickel from the cupronickel cladding, leaving more copper behind. That may be what happened here, or it may simply have been plated or stained.
Here are examples from my metal detected finds of clad coins and even nickels exposed to the elements. Environmental Damage -