The PWC series locomotives and other items usually had a "PW" prominently displayed to help inexperienced collectors identify them as remakes. The conventional classics did not.
PWC rolling stock went through a series of strange changes in truck types, most of which did not match the original postwar equipment. This was the most disappointing aspect of the PWC series, because so many other things were done right. Some sets awkwardly contained postwar rolling stock with modern sprung trucks, some had another type of goofy looking truck, and some, toward the end of production, were furnished with diecast postwar AAR style trucks like the cars in the Northern Pacific Legacy GP-9 set. Conventional classic cars used die cast bar end trucks or die cast AAR style trucks to match the appearance of the postwar equipment. They were even kind enough to get rid of those fast-angle wheels and glossy black side frames that just don't look right, particularly on a postwar remake.
Some sets, which could be considered conventional classic sets, had postwar style Lionel packaging, and were sold to LCCA members. One example is the New Haven 209 Alco AA set with passenger cars. It was essentially a conventional classic set, but with TMCC. Conversely, not all PWC equipment had TMCC, including many operating units.
Then, we had the introduction of "postwar inspired" offerings, which came along about the time that the conventional classics series was winding down. Undoubtedly, the name change gave Lionel's millennial designers the license to go freestyle, and come up with a bunch of wacky products, like the reindeer rocket fuel car. In some cases, like the Wabash 2367, they were truly conventional classic remakes. But for the most part, they were fictional "what if" items offered in different road names, colors, etc. The items offered since 2014 have been very limited, don't have postwar characteristics, and such things as Pullmor motors and remakes are history, as the company is squarely focused on either Nascar or those funny looking things that race around on that coaster track that flexes like a wet noodle.