Järnvägshistoriskt forum

[Hello so I recently found this carriage in model form, I've taken quite a liking to it.
Can anyone able to identify it's identity? I've look up "SJ CDo12t 817" on the internet and found frankly nothing other than this one model image.

And if you able to share it's drawing of the wagon will be greatly appreciate! ...as I'd like to recreate it in digital and illustrated form.

Built by WUMAG for Halmstad-Bolmens järnväg as HBJ CD 800:
Some pictures from Görlitz:
https://sachsen.museum-digital.de/object/12297
https://sachsen.museum-digital.de/object/12298
https://sachsen.museum-digital.de/object/12299

Rebuilt by SJ in 1951 as SJ CDot/CDo12t/BDo12t 817. Boggies and larger post office:

Bildtexterna säger dock treaxlig vagn fast första bilden och ritningen ser år en tvåaxlig vagn. Det var visst SJ som byggde om den till boggievagn.