I know this is an old post, but I actually had a similar problem on my truck (1950 Chevy 4100). When I went to clean off the paint all of the original information was either gone or came off with the other paint. Since I am a Graphic Designer, I figured I could easily fix this. So what I did was recreate the silk-screened original design, then substituted the correct GVW and HP. I went to my nearest arts & crafts store and bought a transparent water slide decal kit meant for inkjet printers. I then cleaned the id plate very well, leaving the VIN # in tact. After printing & sealing the decal with supplied aerosol sealer, I trimmed the decal so that the VIN stamp area would be open. After applying the decal & a coat of flat clear enamel, this thing looks good! In my case, since I am rebuilding & not necessarily restoring, I purposely left some of the gashes and scratches in the plate, and since the decal is transparent, it looks old & faded, but still completely legible.
This is a great fix for those, like me, that have trucks with larger GVWs.
If anyone is interested in a complete walk-through and/or the design for the ID plate (so that you may print your own decal), just shoot me a PM. I would be happy to help.