I don't know the answer to your question, but just wanted to add for reference that almost all the planes on the ERJ series have aisle armrests that flip up on all non-bulkhead seats. On the newer planes, it's a button under the armrest that you have to push in (sometimes I have to use a key), and on the older planes, it's a latch back where the arm meets the seat. I use this to exit the seat to make up for the lack of pitch, especially when the seat in front is reclined.