slant 6 main bearings

I would like your guys opinion on these new main bearings. I bought these off ebay. They were packaged and new but they have something different with them. Looks like they are splotched, stained or something. They are smooth but there are definately different. They are old discontinued Michigan bearings but they were in the plastic packaging when they arrived. The finish doesnt look right and I dont know if I am comfortable using them yet. need your opinions