I purchased some used 308 brass thinking it was LC 99 and 76, but turns out I was looking at it wrong, it's 66 and 67. All says Match or NM (national match?)

Any opinions on if it's safe to fire being so old. Unknown if once or more fired. Looks good though, no cracks or buldges, reasonably clean and bright.

thanks for any input anyone might have.

kc.