that's a cool piece, you should be able too tell something at the chip- shelving appears thick- appears to have wood backing- does the wood backing come off?, so you can inspect the back of sign.. I like it..
Yes Randy you are correct this does have very thick porcelain, and the back is black porcelain what looks to be scuff marks or someone took sand paper to it .
with evidence 57tbirdkid has presented puts this piece in a questionable category- both backs the same, rust on exhibit 1 looks unnatural- both appear too have originated from the same place..