Upgrading Nest Learning thermostat 2nd gen to 3rd gen

[kripster]

I have a 2nd gen that is going out of support and must be upgraded to support remote operation. 

I have a new regular Nest thermostat but the faceplate is smaller - I’m wondering if any other product has same faceplate size saving me from redoing any making of holes. I understand 3rd gen Learning may have the exact baseplate. So two questions:

1) can anyone confirm base plate dimensions and holes are exact? In fact, are all connectors and hardware of plate identical such that I can keep base plate on wall and just swap out top Nest unit?

2) is there any way to get discount coupon for 3rd gen? Google email specifically states discount is for 4th gen. 

thanks

[Patrick_Caezza]

@kripster 

Every Nest thermostat is different.

Your best bet to to look on Amazon or such for a wall plate

[kripster]

Thanks Patrick. I did read online that each plate goes with one gen thermostat only. I opted to use the 4th gen offer from Google. Now I just need to install it!