I'm installing new door panels in my 16 touring. I cant remember if there are finish nails across the center the drive into the wood cross member of the door or are eh finish nails just around the edges??
There is a line of tacks through the center of each door and a line through the center of the false door on the driver side.
Late 16s did not have the nails across the center.
The original upholstery nails were 3/8". They are not available today, but there are some that are close, being 1/32" larger. They are available from Witmer Coach in New Holland, Pennsylvania.