For leather coats dating from the late 1830's check out the works of Alfred J Miller who painted the mountain men of that period. These were either patterned on the frock coats of that period or were a simple coat made of a series of rectangles similar to the way hunting shirts were made. Most coats of this era were fringed at the shoulder and sometimes along the sleeves. Other records from the period note that fringe was a major part of the frontiersman’s clothing from the 1830’s onward.
Several of Miller's works are seen here and can be zoomed in on
http://art.thewalters.org/viewartist.aspx?id=4486#resultsCaped hunting coats based on similar patterns were also popular and the style was worn well into the 1860's, especially amongst the displaced eastern Indians such as the Delaware/Shawnee and Cherokee. Here's a link to a heavily decorated Delaware coat from the 1835-1860 period. This style in leather goes back to the late 1700’s as well , the LaMayeur coat is from that period and is essentially the same as these later ones/
http://www.dia.org/object-info/39cbc78c-f52a-48ef-be2a-63ae95917f26.aspx?position=2a plainer version was also worn -
Here by Black Beaver a Delaware scout circa 1846
the type was also worn by whites - this is Colonel Dodge in 1834 by G Catlin -
As noted above, style did change over time though and by the 1850’s one starts to see hide jackets similar to this one worn by Texas Ranger John RIP Ford
My recommendation – narrow your time period down to 5 years or so when documenting such items. One can use an earlier pattern for the later periods, but not vice versa. 1830-1850 period frock coat patterns are available and the later plain jacket can be based off a basic jacket pattern with the addition of patch pockets and fringe.
I have several more images of 1830-1860 era coats, including the so-called 1850-70’s scout coat, some SW styles, and fancy Metis styles. I will post them later if so desired.