I'm pretty sure the bytes are sequentially addressed, but the program (memory contents) may contain branching, conditionals etc to load the next address. Just like assembly language.
If I recall correctly, the microprocessor logic on these missions was RTL (resistor-transistor-logic) which was the predecessor of TTL.
It was sequential but bank-addressed. The AGC had it's own assembly language[1] and was a pretty recognizable general purpose computer[2] for it's time.
