Anyone good with navajo blankets

I've had this in my possession for a while now. The previous owner was quite proud of it as am I and I was just wondering if anyone was familiar with the seal pictured. It is attached to a corner of the blanket and looks like it once had a paper tag attached. Also, can anyone date this particular rug? It isn't overly ornate and seems more functional, just my style. It's 30 inches square