It is a week 1 of 1984. It is known that the super early serials were botched. Someone forgot to change the year from a 3 to a 4. I have several of these on hand that go with very early 128k made in the first couple weeks of 1984. Super early ones, before the serial was standardized to what we know, were just simple numeric serials in sequential order on a glossy label and believed to be made primary during production test runs, etc up to mid-December or about.
With that said, collectors who like the early serial stuff will put more value in early serials like that. Probably to complete an impartial early system. For myself, I tend to collect 128k stuff that is week 10 or earlier, this is what I consider early.