The threads for the kugel differs so you must make sure you get a kugel with threads that fixes into the base. Otherwise, buying the base and the kugel will be a better alternative.
Good point Amy. I bought a complete spike off a French dealer once and he sent me a kugel and base by mistake - being curious I tried it on my helmets and the thread was too small for all of them. If only I’d known I should have kept quiet and kept it