Pass In “WHERE” parameters to PostgreSQL View?

You could use a set returning function:

create or replace function label_params(parm1 text, parm2 text)
  returns table (param_label text, param_graphics_label text)
as
$body$
  select ...
  WHERE region_label = $1 
     AND model_id = (SELECT model_id FROM models WHERE model_label = $2)
  ....
$body$
language sql;

Then you can do:

select *
from label_params('foo', 'bar')

Btw: are you sure you want:

AND model_id = (SELECT model_id FROM models WHERE model_label = $2)

if model_label is not unique (or the primary key) then this will throw an error eventually. You probably want:

AND model_id IN (SELECT model_id FROM models WHERE model_label = $2)