1916 or 1917 standing liberty quarter?

I acquired two type1 standing liberty quarters for about $10. There are no stars under the eagle on the reverse so I know they are type 1.
I can’t read the dates on either coin (I used 20x) and pcgs has graded a few 1916 standing liberty quarters as 1 with no date visible. How does pcgs determine a coin is a 1916 instead of a 1917 with no visible date?
Also, I do not believe there are mint marks on my coins when I compare them to a 1917s. If there were then I know they are 1917.
I feel foolish posting and asking this question because these coins are in such poor shape but there is a huge price difference between 1916 and 1917 and pcgs has graded 1916 quarters with no visible date, therefore should I take the chance and send these two coins in to pcgs?
Thank you in advance for your advice.
Comments
I don't think it's a 1916. The visible shield rivets are too strong, and the dark fold in the drapery under the extended arm should extend almost to the top of the wall. https://ngccoin.com/boards/topic/245530-diagnostics-to-determine-if-a-dateless-t-1-standing-quarter-is-a-1916/
17 x 2
I’m wonder 01 or 02
@Ppp - Both of your quarters are 1917, no question. No need to send them in for attribution.
Thank you for the quick and excellent replies.
You just saved me some money.
That's what we try to do here............................
Pete
Of course the obvious question is to the value in "low ball" grades.
@CoinHoarder... Great visual aid posted, and will help other collectors as well. It clearly shows the OP's coin to be a 1917 SLQ. Cheers, RickO