Regarding grizzlies in Oregon, there are stories / reports. The ones I have been looking into come from the area around Crater Lake National Park and the upper Rogue River area / southern Cascade Mountains. I would not absolutely rule out the possibility of grizzly or grizzly/black bear hybrids in Oregon but if they are here, they are pretty darn rare.
More likely would be one of the many color phases of black bear we see. I got this little female on my trail cameras a lot over a period of about 3 years. The 3rd season she had cubs, jet black. Her face is black, under hair is black, but the long "guard hairs" are blonde.