I cant say for sure it is without seeing it,but musclewood is pretty easy to identify by its distinct appearence....i have made a bow from it,which has since been retired now,but shot thousands of arrows
Heres what the back looks like,its been dyed a brown color,and i steel wooled the ridges after dying it to highlight the muscles.
![](http://i1181.photobucket.com/albums/x436/blackhawk28/00small25434581.jpg)
And here it is braced hanging on the stump from wence the bow came from
![](http://i1181.photobucket.com/albums/x436/blackhawk28/00small79439551.jpg)
If you look to the right limb tip there is an american hornbeam,and another one to its right