I can not speak to that set....but if oem that is a very good price. Let us know as I need to do timing belt and vc gaskets .
on the other hand....many years back I got a set of Ishino valve cover gaskets, they were advetised as OEM....and said, orignlal supplier to toyota . They fit perfecct and I never had a problem with them. I have looked and and cant find the Ishino again for our engines.
I wonder if at that price point ( the ones you are looking at) if they are something like that. Nothing wrong with that , we know many suppliers are suppliers to Toyota and we can get the same parts....like seals and stuff....cheaper but same company/supplier to toyota. Cabinmans ( ebay) timing belt kits come to mind on that. He sells a DNJ kit valve cover kit for about 70. Most of what he sells is original supplier. and seems he has a pretty good reputation on this forum and other forums for toyota stuff.