It doesn't matter if it's the same exact ship...it's the same CLASS of ship...so much so that we think 'ALIEN DERELICT' right off the bat. And in that ship are familiar looking Giger-like tunnels and a replica of the Jockey chair.
EVERYTHING is absolutely obvious, we've been having these same back and forth discussions FOR MONTHS about this and it's quite frankly like knocking your head against a cement door that's on top of dirt. If people are still questioning Prometheus' connection to ALIEN at this late stage they are either doing it to be funny, or it's willing ignorance.