Yep, stripped and worn but it's fine. A nice Vespasian. Edit: I should ask... what makes you question it? The metal type?
yes metall kind of different from what i seen & own before , also reverse legends why they not corroded as area around them ?
At one time the entire coin was as dark as the space between the letters. It's called a patina. Someone has removed the patina from the raised areas of the coin but left it in the lower areas. I am guessing that you are used to the look of bronze coins, which were an amalgam of copper and time. Your coin is a sestertius. It's made of orichalcum, similar to brass, which is a mix of copper and zinc. That's why your coin has a brassy golden color instead of the usually coppery color of bronze.