Yes it definetly seems darker Osage is denser that's for sure most of the Osage I've worked was light colored but I have some Osage I cut here in Iowa and it is naturally very dark and seems much harder to work then light colored Osage
I second this too. Most of the osage I cut is "normal" as well, but I cut a piece in the hills of Kentucky once that was very dark and dense. It was funny, it was like none of the osage up there grew that big, it was all pretty small diameter, it was weird. The stave had a lot of reflex and didn't wanna give any up. That was when I had just started messing around with making bows, and I had started in on it after only one week of drying!
And it still didn't take any set. I had it bending out to 26" or so probably. I went to string it and the string stretched so much my fingers got stuck in between the string and the bow,
. It was not cool at all, lol. Ended up blowing up due to my shabby ring chasing.
EDIT: Although your piece OP looks like red streaks, which are still good things in my book. I get a lot of osage with red streaks, usually closer to the pith of the tree.