Generally the newer-production runs of any such comparison are regarded as better-built or improved due to the lessons learned from the earlier production runs. Likewise engineering changes or small materials or finishing improvements are likely incorporated without any fanfare. I know Ruger employees who'll concede many lessons from the assembly routers of the first LC9 lots for example.
Romantics favor the "original" productions lots simply based on nostalgia, but then some models had finish options that were/are not available on different runs or distributor exclusives.