I think introduction dates and lifetimes do matter on every rolling stock type, because for example, Finnish Trainset has 5 generations of wagons/coaches/multiple units/locomotives, and I, as a developer of set, would prefer that buying list shows all relevant information in all cases at the same style (with Introduction dates and lifetimes shown in wagons and coaches too). It is important thing, because that gives player information, that when (s)he may begin replacing his/her wagons/coaches with next generation ones.
You could look at the Dutch Trainset, that displays all kinds of additional information in the purchase window already.
Coder of the Dutch Trackset
| Development support for the Dutch Trainset
| Coder of the 2cc TrainsInNML