1920 Or 1930 Standing Liberty Quarter?

Warning: this post contains a lot of pictures

I know this isn't really a big deal but I'm very curious about this. I found it in a lot that I bought. It's a very nice coin but the only part of the date left is a 0. If it's a 1930 I will resell it later but if it is a 1920 I will keep it.

The coin in question:



A 1930 Standing Liberty quarter:




Unfortunately, I don't have a 1920 Standing Liberty quarter to compare with the one in question, so I will do my best.

It does kinda look like it could be a 1930 just by looking at the date. My brother actually strongly believes it's a 3 there for that reason.



However, those spots don't match the style of the 3 on a 1930 Standing Liberty quarter.

1920 did have a different date design than 1930. The 1930 design is recessed so that the date wouldn't wear as quickly. As far as I know, that's the only difference between 1920 and 1930.

1930 SLQ:



19?0 SLQ:



So, clearly, you can see that the 1930 is way more worn than the 19?0. In fact, on the 1930, the M is about level with the rim, while on the 19?0, the rim is like a cliff above the M.

So how is it that the more worn coin has a full date while the less worn coin is missing 3 digits? I personally think that it is because the coin does not have a recessed date and is therefore a 1920. Maybe I am overdoing this but it's pretty interesting.