The main thing that isn't lugged on the newer bike is a part for which I don't know the name ... it's the connector between the seat tube and the top tubes. Sounds like yours is the same as my older bike so that would put it on the older side.

The other noticeably shoddier aspect of the newer bike is that instead of having a clean line on the top tube as it comes down to the rear wheel, the new one is bent outward on the chain side. The first time I saw that I thought the bike was damaged, but now I've seen it on several late model low-end mixtes. It's really ugly and it doesn't give me a lot of confidence in the frame.

The older Nishiki is, as I said, a very sweet bike. If yours is similar I think you'll be happy with it. We stripped mine down just about to the frame and rebuilt it as a single-speed townie, and I get so many compliments on that bike (and offers to buy it!) that you'd never know it was a $35 garage sale bike, and a low-end model even when it was new.