Imhof Carriage Clock.

Hi,
Recently acquired a perfectly working, accurate Imhof, it has a seconds hand, beautifully engraved machine, encased in gold plated brass and glass.

How rare is this model and did it originally come with a rear door in acrylic, as compared to the front and sides in beveled glass?

Any history about this beauty, from the learned forum members shall be highly appreciated.
Thanks.