Correction
I should have looked at the Andrew Dow book before I posted. The first 8,500 N&W HL hoppers had fishbelly sides but the last 4,000 HL's and all of the H9's that were rebuilt from HL's has sides that were straight from bolster to bolster. The sides would also have to be modified to produce an accurate model of the later HL's and the H9's.
Larry Kline
Pittsburgh, PA