Squarish vs Ovalish Spark Plug Seals

[RainierGT]

I need a right side(passenger) valve cover with the square shaped spark plug seals for my EJ25D. I can't find one anywhere- wrecking yards, eBay, the dealer or Craigslist. I spent all weekend installing remanufactured heads from Machine Shop Pros and both heads they sent me have the squarish shaped spark plug holes machined in the heads. The motor I got from the wrecking yard had one head of each variety. The passenger side was the normal oval shape and the drivers side was the odd square shape. Consequently, I now have a passenger side valve cover with an oval shape spark plug hole that I can't use. The dealer is absolutely no help. They think it might be a Japan only spec. The HG set that I purchased came with both type of spark plug seals. Does anyone know where to find a square type valve cover? Thanks!