Great find Congrats! I remember them in circulation as a kid and those babies were usually worn like yours! My neighbor called them, "Cowboy Quarters" because he said the wings on the Reverse side, when held upside down, looked like chaps worn by a cowboy!
I worked in a local Mom & Pop store when I was in high school in the late 1960s.
Silver was still circulating then but was quickly being culled and replaced with clad -- nevertheless, I found a large number (well over 100) of SLQs during the four years I worked there. Every single one that had any portion of a readable date was from 1925 on (when the mint recessed the date because it wore off too quickly because it wasn't protected by the rim).
Even with the recessed date, the coins often had barely readable dates.
I did find a type 1 1917D quarter but it is recognizable by its design and mint mark. The date had long since worn off but the devices like the rim and feathers were fairly well defined.
I've never found one, but I once bought a bag of junk silver from my LCS and 1/3 of that lot was near-slick SLQ.
I paid $6.75x face value for that buy (around 2004/2005 timeframe). I had a friend who had a vending machine business in the same building as my LCS so I bought a sour apple gumball from one of his machines with a SLQ. I figured I would tell him about it and it would encourage him to finally search some coin. He said it wouldn't be worth his time. So, that SLQ made it back to the wild. The rest are still in my stack in SDB - or so I assume. I haven't seen my silver hoard in close to 3 years (nothing in or out of safe deposit box in that whole time).
My bucket list of type coins found from CRH is all coins from roughly the seated liberty time frame forward. Here are what I am missing that I think are at least somewhat possible as they have been found by others on this forum over the years, even if rare.
cents
* flying eagle cent
nickels
* shield nickel
dime
* none - have found at least 1 of each type from seated liberty forward
quarter
* seated liberty quarter
* barber quarter
* standing liberty quarter
half dollar
* seated liberty half dollar
There are a few others on my wish list instead of my bucket list as I see the odds of these as all too low to be really possible and they are:
* 2 cent
* 3 cent silver
* 3 cent nickel
* 20 cent
* seated liberty half dime
* seated liberty dollar
* trade dollar
* anything larger than dollar (eagle, double eagle, etc)