Hi mate,
Ive got 2 84's and have done this build and spent alot of time speaking to people about this.
All i can say is that if the serial number is on the left rear drop out it is a US made frame.
Send me a pic and i will tell ya.
If the serial is under the BB it is deffo a Jap made.
Wardy had the only frame that went against everything that is written about how to identify US and JAP framesets.
If the serial is on the left rear it is 100% US made.