Will have to re-watch, but yes, it seemed like a classic to me when I first saw it. I expect my initial opinion will be confirmed.

Other movies are the reverse: they seemed like classics when they came out, but time has not been their friend (e.g. Gone with the Wind).

Some films were criticized / reviled when first released, but time has heen their friend (e.g. Rules of the Game).

How would you place Cheyenne Autumn, Kiss Me Deadly, and The Long Goodbye? All three question the genre to which they belong (as does Unforgiven).