Master cylinder residual pressure valve

I have another brake issue thread but, this is a general question. Do the new style aluminum with plastic cap masters have a residual pressure valve? It seems s number of folks here are using them. I talking about Raybestos MC39178 or Dorman M98894 and several aftermarket. It doesn't look like enough space to have a valve under the seat. Most fit a bunch of 80s cars and trucks. I cant find the that info anywhere but, I have read about it being used on disk-disk. Craig