I also would like to find this info. I sang this in high school in the late 60's. I seem to remember it being called Weep, O Willow but can't find anything on Google wither.

On a big black horse he came riding into town,
On a big black horse rode he,
He talked of love with a smile upon lips,
He talked of love to me.
O-o-o-o-o, he talked of love to me.

?????
I saw his smile in the brightness of the moon,
But the smile was not for me,
o-o-o-o-o, but the smile was not for me.

I saw him fall in the middle of the road,
A gun wound in his head.
??????
O,o,o, my love is dead

That's all I can remember.