I believe the C60S and Ford F60S models were mostly used for 'special' bodies rather than being fitted with the cargo GS bodies.
The tanker variant would have had a different style of spare wheel carrier.
Were there two types of those carriers you have pictured , for the 16" and a bigger one for 20" wheels ?
A Ford CMP tanker used to turn up at Corowa years ago .
pics
https://www.awm.gov.au/collection/C65862
https://www.awm.gov.au/collection/C65836 (Appears to be the short 200 Gallon version)
https://www.awm.gov.au/collection/C46236
https://www.awm.gov.au/collection/C207968
Looks like there were two local CMP versions: a short 200 Gallon and a longer 400 Gallon tank.
https://www.awm.gov.au/collection/C207828 The MCP type with 200 Gallon tank.