Your question only applies to ashkenazim because sephardim all pronounce it cholam.
My husband says that the German pronunciation is more accurate and only pronounces an “oy” if it is a choylam maleh (with a vav) rather than for a cholam chaser (just a dot over the next letter).
I wouldn’t generalize as to where or how a person learned to determine from how they pronounce this vowel. I’ve heard lots of frum people pronounce it cholam even though they are pretty yeshivish. Why does it matter what their background is unless you plan on pegging them into a particular stereotype.