In David Herd, Ancient & Modern Scottish Songs, Vol 2, first published 1776, are 60+ lines titled The Dreg Song.

It seems reasonable to suggest that – like the text given in the Digital Tradition – the lines are less a song than a series of children's rhymes strung together.
They include the following:

True note, true song,
I've dreg'd o'er long,
O'er lang, o'er late,
Quo' the haddock to the scate
Quo' the scate to the eel,
Cock na I my tail weel?

Note two different pronunciations above – long / lang. Two different songs, or what?

Anyway, the final lines of Herd's Dreg Song are this:

Jeery ory alie;
Weel row'd five men,
As weel your ten (I think Archie sings As weel as oor ten) The oysters are a gentle kin,
They winna tak unless you sing.
Come buy my oysters aff the bing,
To serve the sheriff and the king,
And the commons o' the land,
And the commons' o' the sea.
Hey benedicete, and that's good Latin.

Where Archie got the tune from I do not know.

Ewan McVicar