in cab Fuel Tank opening c40-70 ?

[greywuuf]

Just curious, My C60 has has dual 65 gallon saddle tanks, does not apear to have ever had an in cab tank but it Does have a Hole for the filler..... Cab change ? ( still has all the original door jamb plates and such so I dont think so)..... were the cab chassis shipped out with an in cab tank and that was left to the bed installer/ end user to change/deal with ?

Do most/all medium duties have filler holes, none some ? is mine the only one?

Any one have any insight ?

Thanks
Dan