Historia is 4'7 so in other words, she is short. On the other hand, we have Mike Zacharias who is 6'5. Do they have the same size gear or is it custom made for them?
Back during the Female Titan arc, Armin recognizes that Annie was using Marco's ODM gear. So at the very least, they are unique enough to be told apart if you are familiar with them.
Then again, most of the fitting of the ODM gear is done through leather straps, so it's not like you would need much customization to tailor it to each soldier.