Both lower-end and higher-end frames lacked chrome! Depends, too, on when it was made, and by whom. Until the mid-1980's, chrome-plated rear dropouts and fork ends were pretty common even on high-tensile steel frames not made from chrome-moly steel.

What's more important is to look at the ends themselves. If they have markings that indicate that they're made by Campagnolo or Shimano, they're forged and the frame is high-quality.