Oh yes, i think there probably is, although with only two, with plenty of space, they often become great friends and it's not so evident because there are fewer times when one actually needs to obviously take charge. If you ever get more hens, you'll find it becomes clearer in a larger group, as the interactions are more complicated and there are more rankings to be filled. A lot of interactions between hens are very subtle, a matter of glances and glares when another lower-ranking hen steps out of line, reinforcing previous lessons learned the hard way when the flock was settling down together after introductions. Also each hen has a different personality, some are more of a leader than others, and this depends a lot on the breed. The sort of commercial hybrids who are bred to lay every day in very crowded conditions are usually bred to have placid temperaments and often aren't so bossy or competitive, as this would cause stress and reduce productivity. My strangest pairing was between two 5-week-old chicks, a Buff Sussex and a Cream Legbar, who grew up together and were kept separate from the older hens for 3 months. The Legbar was very clearly in charge from the start, in an amicable way, appeared much more intelligent and a natural organiser, and obviously told the Sussex where to go next, what to eat, when to roost etc, but never seemed to be aggressive to her larger friend. The Sussex died this Spring, and the Legbar is still top hen, age 5, in a flock of 5 younger adults, including a 4-year-old leghorn who is always trying for promotion to the top job, but hasn't made it yet!
I think watching a flock and realising the subtleties of what is going on between them is one of the chief joys of keeping hens. It will be interesting to see what others have to say about their observations.
Anyway, I'm glad Gertrude is O.K!