Respectable people in general.

1

1840.  Why law! it ’s a rattlesnake; the Indians call them Massisangas [Massasaugas] and so folks calls ’em so too.—Mrs. Kirkland, ‘A New Home,’ p. 33. (Italics in the original.)

2

1844.  There was considerable earthenware and silver teaspoons, and it was evident they had lived like folks.—Miss Sedgwick, ‘Tales and Sketches,’ p. 200 (N.Y.).

3

1867.  

        ‘Why, where in thunder was his horns and tail?’
‘They ’re only worn by some old-fashioned pokes;
They mostly aim at looking just like folks.’
Lowell, ‘Fitz-Adam’s Story.’    

4