The birth and baptism dates both contain the same date.
It is possible, though unlikely, that he was born and baptised on the same day.
Birth records in this period are rarer than baptismal records which make it more likely that he was baptised that day and no record exists of when he was born (could be several months between birth and baptism).
However, if the birth date comes from a later record, such as marriage papers or death record, it could in fact be a true reflection of his day of birth.
Without knowing the source of the date it is impossible to guess at its significance, nor its correct placement.
So, where does the date 28th April 1604 come from?
NOTE: His recorded age in the ondertrouwregister of January 1624 is 19 which matches a birth date in 1604 but does not shed any light on the question at hand. I have not yet located the actual marriage record.