A good source for hard to find WW2 German rifles is a German company called Sauer Militaria. They sell mostly de-activated, but they also sell original K98k's and such.
I have been a customer with this company for quitte a few years and they have a good service record, with me as I may say so.
Here is their website, www.sauer-militaria.de
I am not connected in any way to this company, just letting you know what is out there in Europe.