This is the designers initial.
I assume you mean a silver certificate, not a dollar coin. Values range from $6 if worn, up to about $35 in near-new condition.
No such thing as a "Eagle Mark" on any US coin. If you mean a mintmark? They are little tiny letters on the reverse of the coin, and can only be a D or S on this coin.
Do you mean, what's it worth? If the coin is in a collectible condition, retail values for circulated coins run from $30.00-$43.00.
If you mean the spelling if the word trvst, it's not a mistake all Peace dollars have this and the coin is only worth $16.00-$18.00 depending on how much wear the coin has.
The coin was minted in Philadelphia, PA.
The hole was used to tie a string in order to recover the coin once the coin was used in a vending machine .
No US president has been on a SILVER (1794-1935) one dollar coin, but if you mean a large one dollar coin dated from 1971 to 1978 made of copper-nickel, it's Dwight D. Eisenhower.
If you mean a 1998 Kennedy half dollar, the coin has no silver in it and is worth face value.
The term "key-date" means a more valuable or scarce coin of the series. But the 1923 issue is not one of them.
Still no 1942 silver dollar US coin. If you mean a 1942 US half dollar it's worth $7.00-$9.00 in circulated condition.
What does "binion" mean? It's not in any dictionary. If you have a regular Peace dollar, see this link:
The US issued no silver coins of any type in 1979, but if you mean a 1979 SBA dollar coin, just spend it.