This is one of the broadsides Steve listed of which I've found three printings and there may be more. I've also found a different version titled "Young Molly Bawn." Here are the three sources. The date is circa 1850s. The unusual line is: "My curses on you Toby" whatever that name(?) means.
1) An Admred Song called Young Molly Bawn --Crawford.EB.1875 [Dublin? : s.n., ca. 1860?] National Library Other title: Rocking the cradle.
2) Imprint Names: Nugent, J.F. & Co. (Bodleian
3) An admired Song called YOUNG Molly Bawn; single sheet with Breennan on the Moor (Bodleian)
An admred [sic] Song called YOUNG Molly Bawn.
Come all you young fellows that follow the gun, Beware of late shooting by the setting of the sun, Her white apron about her I took her for a swan But to my misfortune it was my Molly Bawn.
He ran to his uncle with the gun in his hand Saying Uncle, dear Uncle I'm not able to stand, I've a story to tell you which happened of late I have lovely Moly Bawn and her beauty was great.
Up comes his father and his locks they were gray, Stay in your own country and don't run away, Stay in your own country till your trial comes on, And I'll see you free by the laws of the land.
My curses on you Toby that lent me your gun To go a state shooting by the setting of the sun I robbed[sic] her fair temples and found she was dead A fountain of tears for my Molly I shed.
I shot my own true lover— alas? I'm undone While she was in the shade by the setting of the sun Ah, if I thought she was there I'd caress her tenderly, And soon I'd get marred to my own dear Molly.
Young women dont[sic] be jesting when your love is sincere, For if you do they can't love yon or e'er as you care, You'll know by a young man's conduct, when he's gentle and bland [T]hat he'll give you his heart and also hi[s] hand.