The 68 parts manual also shows Full size Chrysler, Plymouth, Dodge with the 440 having a 2898063 radiator with the 22 inch core. So yes the GTX could have a 22 inch according to the parts manual. As said if you were a betting man the 26 should win the bet. However there is no doubt they are out there. It would be nice to have more information to back it up. The radiator may have numbers that could help prove or un-prove its originality.
so much misinformation
the GTX isn't a full-size model
the 4-speed manual was NOT available in a C-body with a 440
