The LP is called "Wednesday Morning 3AM" and is the only LP by them I don't have. I do know it's their first when called "Simon & Garfunkel".
Before that they went by the name (and no I'm not kidding) "Tom & Jerry". I think for 1 LP. It is true that it was that 1st acoustic version,then it was "re-dubbed" (no "re-mix" then) with more instruments.
It worked though,the song went to number one during the very last few days of Dec. '65 into Jan. '66. Over 40 1/2 years later,
it's still a song people really like. Mainly because people today,like then,can relate to it's "lonely" sounding lyrics.
I'm sure including it in "The Graduate" film helped too.