Why the difference in SJ cockpit from Alien and Prometheus ?

There was a prior thread with two distinct pics of the cockpit in the direlect from Alien and Prometheues. This is my opinion as to why one looks scaily and biomechanical via alien and the other looks more mechanical via prometheus. I think with all the Theories floating around that the possible theory of the Zenomorph or alien being a result of a mistake fits as to why the derelict looks different from Alien and Prometheus. I think the Bio and mechanical gap was merged after the Zenomorph was created helping alter the ship and there is a possibility what ever bursted out of the SJ's chest may have helped change the environment into a hive on the derelict in Alien giving it a biomechanical look. The dirilect in Prometheus shows the true SJ's mecha and how it's more mechanical with the aid of genetics but not so fused into one.