Both of those might introduce a problem. Turn the servo around, and you've just changed the length of the pushrod. That'll make it difficult to get the same travel, which is likely to be just a little important. Using the other side of the servo arm may not be a great option, either.

There are two real solutions. The less expensive and less ideal solution is to by a servo that has been reversed, so that you can use it with a Y-harness. The much better solution is to buy a radio that supports dual elevator servos. Why is that a better solution? Because you then have the ability to independently adjust each servo. It's tough to get two linkages to be exactly the same physically.