assembly is not a building its their version of population
building assembly increases the planets population by 2

 if your looking for a buiilding that increases manufacturing you want the manufacturing Yor building i think its 2 above assembly on your SS

nope just adds 2 population thats all 

that's not population cap either that's 2 billion extra Yor walking around on your planet

there are more 'buildings' like this that will unlock with the yor's population line they do essentially the same thing but add 4,6,8 population instead