1937 Special Tail Lights

[bobj49f2]

Are the left and right tail light housings the same? I have a couple of sets of tail light housings. One set I just took off a set of fenders and have marked "L" and "R" and when I hold them up next to each I think I can see a difference in the slant of the bases but I can't seem to figure a way to accurately measure them to see if there's a difference. They all have the same casting number, 920738, three have diamond and a "2" above this number and one has a "1".