public boolean isSignatureMissing() {
		return mtyp == 0 || mtyp == NumericUtilities.MAX_UNSIGNED_INT32_AS_LONG || mtyp == -1;
	}
Returns true if the funcdef is missing for this method.

@return true if the funcdef is missing for this method
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/golang/rtti/types/GoMethod.java