Embraer may have had production slots for the E195 available because the 190/195 have sold significantly worse than the 170/175 due to most U.S. carrier’s scope clauses.
When it comes to final assembly of the 170/190, there is no production line as on the ERJ-145 series, the 800th example of which is expected to roll out in April. The big jets are being built using a dock system, in which it is the tools and materials that move rather than the aircraft. This is Embraer’s way of compensating for the different build times of the 170 and the 190. Maximum capacity is 11 aircraft per month.
Haven’t been able to find anything more recent to indicate a different production rate.