Mattias,
Your modeling skills are quite impressive, but your attention to details I find somewhat lacking, especially for payware. Are you sure the siding on this car is properly oriented. The original 1912 car diagram shows the siding vertical. Later versions show the siding horizontal as you have, but on those cars, the horizontal bracing between the diagonal and vertical bracing was not used. These horizontal braces were used only when the siding was mounted vertical.
And your rivet and bolt placement leaves a lot to be desired.
https://cdn.shopify.com/s/files/1/1189/0286/products/2018-02-13_090114_compact.jpg?v=1519090336
Furthermore, for horizon siding, your model has the width of each piece at approx. 3-1/4" and on the prototype the width is 6" to 7".
In my humble opinion, this rendering might be acceptable for freeware, but not for payware.
David A. Petersen
Dap