Hi David, sorry to see noone else came forward.
The DLX 79 is of pot metal, as other carbs in that series of bodys, 75,76,77,97,102,112,113,114 and further.The threads can be replaced with turning down the stem and press on a brass sleeve with threads, or the stem can be cut and drilled out and a brass insert can be pressed in the stem that replaces the lower part.
Sch. and Linkert parts is similar and in some cases could be cross referenced, but there is differences that Tom is an expert in.
Tom Cotten is just one that restores Scheblers and Linkerts and he can answer all kinds of questions about them.
liberty@npoint.net