RD combo cab rear panel orientation

Just scored a RD210-100 that I will A/B with my recapped RD112-65 and decide which to keep (who knows-maybe both).. Anyhow, does anyone know the original orientation of the top rear panel -- the 112-65 had the straight edge on the bottom and the u-cutout on top (really tight fit against the power cord however). The 210-100 is the other way with straight side up. Then I see some web pics with the "top" panel on the bottom and vice versa! Not a big issue but I wonder what the original design was...