antique waterman eyedropper fountian pen # 42 1/2 nib waterman ideal r.e.g. u.s.a.

antique waterman eyedropper fountain pen # 42 1/2, nib waterman ideal r.e.g. u.s.a. this is around c1920's era.... Has spiral insides, in very good condition... also gold colored overlay... can you give me an estimate??