I don't see any wear on the 1923-S. I would bet that one is MS. The other two are so hard to tell in the photos. I see what looks like rubs on the 1920-S cheek bone and posterior jaw. The 1921-S is super hard to tell with the lighting. So, I'm gonna shrug my shoulders on the 21-S and say "I dunno."
Well the 23-S is the better one of the three in UNC, so that's good. I have very little experience grading Lincoln's, but I know that with some of these with early dates, you can't rely on the wheat stalks to determine wear, due to the muddied strikes.
It is true...one of the best examples is the 1922 No D cents. Search the HA archives for high grade examples...they are MS but look like VF sometimes. It's amazing. If it were me, I would look at these close under a good light source. Even with brown coins, you should get some luster left. Look for any breaks in it...any matte areas on the high spots. That will tell you.
I only see two coins, maybe internet glitch but I dont really think so, they appear AU but don't quote me.
Yes the 1920's were a bit rough for cents when it came to strike. Especially, those from San Francisco and Denver. I have several with great strikes from Philly however. I like all three of these. The 21s could be 55-58 imo. The other 2 should go as high as 63 imo. Beware the woodys though like the 23s. TPGs always grade them low, atleast from my experience.
This was my first thought as well. The 23-S looks a bit odd to me (potentially altered surfaces), but I do think it's the nicest of the three.
The first two definitely look AU-58 to me. The third one could possibly be UNC, but I'd have to see how the luster plays on the high points when I rotated it under the light. I'm not a huge fan of the woodgrain, but I know some people go crazy for it.
IMHO they are all nice looking coins! The 21-S looks like wear on the wheat ears, the 20=S and 23-S could be weak strikes but under higher magnification the 23-S looks like it has fine lines across the entire obverse including the bust of Lincoln. Normally I would think of this as being cleaned but with the minting process 90+ years ago, I just don't know. Those with more knowledge and experience than me could advise you as to whether they are worth sending in to be graded.
I think they all are AU detail coins. All the surfaces seem to have a unnatural shine to them. That's just my opinion, and I've been wrong before.
Heavy wear in the obverse fields and portrait - look at all the marks. Lots of minor ticks on the reverse devices. All wheat lines show signs of wear, the tip of the of left wheat shows the lines are almost merged from wear. Now that I look again, I'm firmly in the 45 camp. It's a very nice cent still!