Nope. Mintmarks were hand-punched until 1990, meaning that different coins can have different mintmark locations. Keep up the hunt!
I'm sorry. I meant the style of the mint marks. One looks like the Tall S Style and the other to me looks like a Serif Style.
You have a large date and a small date coin. One "s" looks as if it may be a "Knob Tail" style. The other one looks as if it may be a " Sans Serif" type, but not sure of the last one.
I think they are both large dates, and the mint mark on the coin bottom left has some deterioration at the mint mark's bottom curve, and dirt in the top which gives it a different appearance.
Hard to say. An overlay of the mintmarks may help. The diagonal of the S looks more horizontal on the "thin" S but it might also just be a matter of die polishing causing a thinning of the curves of the S.
1970-S only had 1 mintmark style, the MMS-008: tall mintmark. Confirmed by both varietyvista and the lincolncentresource.com.
I looked on those sites also and know there is only one MM style for that date. I thought the one looked more like it has serif style properties instead of just being a normal looking S like the tall S.