Which is it: Pelvis
The darker bones on the right are the bones that were found at the Kotzebue site my office worked at in 2008.
The lighter bones are mostly from the University of Alaska Museum's comparative collection. Only the harbor seal bone is from the ACZ collection.
Even with whole bones or near whole bones, it is still difficult to make an identification with the bones you have because of individual morphological differences. Sometimes identifying to the genus rather than species level is acceptable as it is better to be conservative than untrue.
These pelvi are not all from the same side of the animal, however the acetabulum (hip socket) is facing up on each of them. Identifying features should make it easy to tell one side from the other.