I'm now the owner of a vintage Kitchenaid DW and Gibson range!

[norgeway]

Gibson oven....

The oven in that Gibson range was unique in that the oven floor is made of stainless steel and dosent chip or craze like the Hotpoint or Westinghouse ovens with concealed units.

 

[henry200]

oven bottoms

I noticed the steel oven bottoms the first time I saw the Gibson my friend in Florida has.  It makes perfect sense to avoid the crazing issue, plus it makes cleaning up burned-on spills much easier without the risk of scratching or dulling a porcelain finish.