Its a large date with a small die chip around the S, also indicating its probably not a proof. its hard to tell from the pictures, but heres mine its a LD Proof.
Ive collected on and off a long time, just past couple years got back into it. mostly modern, and Lincoln cents.
Chadddr the plain 1970-P does not have small and large varieties just the S, Ill show example as compared to yours. notice the loop on the 9. It will point at the 7 instead of the Mint mark. a lot of large date have a high 7 that's where people make a big mistake of paying too much.
Agree that all the coins are large dates except the photo above. On business strikes LIBERTY will usually be weakly struck (not on proofs). The curl of the 9 is a key marker. Look at the arrows in this photo. Inside the 9 the end point is SHARP, and on the LD it is blunt. The height of the 7 is also a marker. High 7 SD, low 7 LD. Here is a handy reference comparison:
