Tile shower drain problem

I have just removed a ci shower drain and found that under it is 1 1/2" copper pipe. This is a concrete slab house. I live in Oklahoma. Is this right?
This ci drain had a threaded coupling in it and then it was soldered to the 1 1/2" copper pipe.

Thanks JohnT

 

maybe when the house was built. I don't know when codes changed to require 2" drains. A 1.5" drain will still work but only over a shorter distance.

david

 

I was just wondering if I have to use cement to secure my new smaller flange drain? It moves side to side and up and down a little. Can I use the deck mud under the flange to tighten it up and level it? I still have to put a slope on the floor then the pan and then more deck mud.
Thanks JohnT