Boar bristles were used in the leather trade as "needles", but mostly for crafts such as shoe making/repairing where a curved "needle" was required - they still are used today although filament fishing line has mostly replaced the bristles.
Steel/iron needles were used extensively as well.
Like so many tools it depends on which particular craft or sub-craft that decides the need - there were and are generalized leather craft tools, but there are also specialized ones. Most crafts in England and the Colonies were closely controlled by the various chartered guilds.
Also, I'm trying to get my hands on some true bark tanned leather. Unlike ordering a piece of 3-4 oz leather from Tandy, it will not be a uniform thickness.
While that may be true of some current small/home based operations, it is not necessarily true of period leather at all. Prior to the advent of the mechanized leather splitting machine, leather was thinned by shaving it during the currying process - they used a broad, straight edged, two handled knife (similar to a draw knife) and a flat beam to thin leather to a uniform thickness, rather than the curved beam one used/uses when prepping skins for tanning. Earlier on they used what was then known as a round knife, a full circular blade sharpened along the outside edge with a hole in the center to grip with.
Most commonly called veg tanned skin is in fact bark tanned, although the more PC oak bark and hemlock bark are not as widely used as they once were. Sumach is still used on a small scale, mostly in England, and it is excellent leather.
Many if not most large scale modern tanneries (of which I believe there only three left in the USA today) use quebracho bark or a "liquor" made from it to tan with. Muir and McDonald of Dallas, Oregon. sells hemlock bark tanned hides and
www.braintan.com offers bark tan as well, but I'm not sure of the source.
Other excellent leather craft history books of interest are those by John Waterer, who was the one time director of the Museum of Leathercraft in England - they are usually difficult to find since they are out of print and usually very expensive if and when you do find them so I suggest inter-library loan. Also one of The Books of Buckskinning (#6 I believe it is) has an excellent article by Steve Lalioff, well known craftsman and student of 18th Century leather craft. Another of the BOB's also has a fine article on period bark tanning and the tools employed.
Overall the basic tools for European based leather craft have not changed much - not all of the following are absolutely required to make a bark tan pouch, but are what a professional crafter of the period would have used:
various knives - of which only is really needed
linen or hemp thread
beeswax or beeswax and pitch mixed for waxing your thread
two harness needles
a stitching clam or horse
stitch marker - either wheeled or a pricking iron
overstitch wheel
stitch groover
a smooth faced hammer
edge burnisher
punches for making various size holes
FWIW - I've been studying the craft and it's history for 48 years......hope this helps