I'd contact the Art Institute of Chicago, here's a link to their departments: Departments | The Art Institute of Chicago
They have a good collection of Mathey's etchings, etc. and may shed some light on what you're looking for.
seems like they don't give information or values apart from what they have them self's.
think i got some links that they provide so i'm giving that a go.
never realised how hard it is to get information when it comes to art work, well this etching anyways.