There are lots of examples of half stocked heavy caliber plains rifles made by many smiths that weren't named Hawkens. Although the vast majority were produced as percussions, with out a doubt some early ones were flinters. When the Lewis, and Clark, expedition returned, with news of the wealth just waiting to be harvested, in the west, and how well the 1803 Harpers Ferry rifle performed in the field, I suspect many smiths adopted more than a few of this guns features. No doubt many were half stocked, and likely large caliber. I have seen pictures of fine plains rifle made by many of the Pennsylvania gun building firms, as well as similar offering from Steven O'Dell of Natches Miss., J.P. Lower of Denver Co., and Joseph Craig of Weaverville Ca.
I applaud your resolve in resisting the temptation to pro due another Hawken rifle. Good Luck.
Hungry Horse