I can make a guess based on what I know of another D44. This is one I removed from a '77 parts rig, 3 22 7 A5 603780-3. It looks to me like the date here is 3 22 7, or March 22, 1977. I don't know what the A5 means, maybe a shift code or something.
If this is correct then I expect 603218-4 2 8...