The poem seems to be earlier than 1892. There's a reference to it appearing in the Australian Journal in 1890. Fiction Mags Index).

Elsewhere I found a copy saying reprinted from The Yankee Blade with permission of the author. The Yankee Blade seems to have been a paper published in Waterville, Me, 1842-95 (info from LOC), but it doesn't seem to be digitized at LOC yet, so I can't get a date for the poem's publication there. However it was also reprinted in The Livonia Gazette(pdf) (that's a google link I haven't bothered to unravel!) on Friday, Aug 29, 1890 from The Yankee Blade, so I would guess it appeared sometime round about 1890.

Mick