Authentication Help Needed

hi all,
i went through my 1970 S cents tonight and think i have a couple of small dates in really good condition, numbers line up and the 9 points toward the 7 not the S. can you give some advice on where to send these to authenticate them, also how much it costs and turn around time etc? i've never done this before and don't want to mess it up.
thanks in advance,
atticus
i went through my 1970 S cents tonight and think i have a couple of small dates in really good condition, numbers line up and the 9 points toward the 7 not the S. can you give some advice on where to send these to authenticate them, also how much it costs and turn around time etc? i've never done this before and don't want to mess it up.
thanks in advance,
atticus