3640427, is that correct & clear on the radiator?

from '72-'73 light & medium duty truck Parts Catalog:

3640424 = '73 light-duty truck w/400 & 440 inlet (upper) radiator hose
3640425 = '73 light-duty truck w/400 outlet (lower) radiator hose

shruggy HEAVY-DUTY truck, maybe '74, maybe Motorhome ??