It could be, but probably just a popular copy. Many jewelcrafters use the old norse symbols without really knowing what they mean. Since its embedded within a heart that is probably the case, since the old norse did not use the heart symbol. Very nice pendant nevertheless
I just think that visually it would give it a nice contrast and make the pendant stand out a bit more. I really love the natural look of the pendant and I understand the association with green, but I think blue would be more effective.
However, that's just my two cents. The DA community seems to love it, so don't worry about it too much. If you're curious you could select the background in photoshop and give it a blue tint, you might see what I'm getting at.