outer water jacket o rings

[stuart wizy]

ive just rebuilt an fd using rotary resources o ring kit and found that the outer water jacket o rings are not square, ie- taller than they are thicker with a seem mark on the thinner side, its states they must be installed with the tall side facing up when sat in the groove.
are mazda outer o rings like this or is it just rotary resources that make them like this:2Rolleyes ?

[Jit]

the mazda ones im lookng at right now arent square cross section

[stuart wizy]

do they have a mark on the thinner side then?

[Jit]

nope, the thinner side is dark blue (or black) so any mark wouldnt be visible. I thought it was only the inner one which had the seam for aligning with the port?