Roy, If you mean the I.D. Tag for the LH door jamb,here's where I got mine for my '50. Truckandcarshop
I would have posted a direct link to the part but was having problems navigating the site.
For the AD series ones they're on page 115.
I hope you have better luck than me!
Jock thumbs_up

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.