Darlene , welcome.
I have had a number of clients over the years who have nursed their
adopted babies, probably more than half did have a full milk supply
after varying lengths of time. Some became dependant on the
supplementer used but enjoyed  breastfeeding and didn't think
about amounts produced.
Recently  Dr N  and I have worked with a mother who pumped and
used motillium and fenugreek for a number of months before her
baby arrived ( 2 adoptions fell through).  By the time the baby arrived
the mother was pumping 16 ozs per day (about 500 ccs) and had
milk in her freezer. So far both are doing very well.
I'm new to lactnet too so this topic may already have been discussed.
You may want to search for further info.
Ruth Bacon IBCLC  Thornhill Ontario