I'm not sure that it matters. I don't think so. I took apart my floyd once. It's an original Ibanez Edge. Cleaned it all up.

Also... I know what you mean about the plate missing. It's a drag to try and get your block back in.

A little trick i learned is to take the little brass ring you cut off the end of your strings, and put one in that hole. keeps your block from sliding down. :)