Found the catalogues for both Walker and his son, the son's dated 1839 and the father probably c1830 which are almost identical so GW Jr was mainly reproducing his father's stock at this point. Neither catalogue contains any copy of Buffalo Gals and stock number 3 has 2 different songs. The copies in the Bodleian flagged up by Joe have a look of about 1850 in print style and I would guess they are from a later series produced by GW Jr using a new set of stock numbers. The encasing of these stock numbers in square brackets may be significant. We are currently working on broadside printer dating and this should all be sorted out when we get round to it.