The story of how the pies became Ho-Made relates to WWII home-front scarcities. Apparently large pieces of lumber were hard to come by when the first sign was made and the sign painter left out the letters M & E because there wasn’t room for them. It wasn’t until much later that Ho-Made took on a new meaning. The restaurant decided to go with the flow and start promoting the new meaning.
Here is the esteemed arbyreed’s description of how the Thunderbird’s pies came to be ho-made.