I have a strong feeling the first batch of 5 will be numbered 1720-1724 and the second batch of 6 be numbered 1820-1825. I’m just speculating here, but it doesn’t seem unreasonable considering the Arbocs being 1020-1024.
Also, the 1700/1800 buses come with no engine door fan (vent in rear door), the fan has been moved to the driver side. Can be seen on buses 1618-25 ish as well, as they are retrofitted. (Door vent remains, but fan has been moved)
Also my source told me that the new buses have USB charge ports through out the bus, even the front wheel well with the window seat has one.
Lastly, interior advertisements can now be placed on both sides of the bus interior. Similar to the recent TTC novas.