The only help I can offer is seeing the parents is a great help in determining the 'look' of the babies but no guarantee from what I've read - also - I don't think Roach backs really show until the puppy has matured a bit -    
I am by far NOT an expert so I'll stop here - but you can go thru this site and type in search words about choosing a puppy and you'll find great information here....Many people are not able to see both parents.... and if you can do that -you have a great start.   
Desi is adorable !        |