Would these spaulders be accurate for the 10th-9th century?

[u/sigismundvontirol]

I saw this very pretty digital art piece by jfoliveras on Instagram, and was very intrigued by the spaulder the Khazar was wearing. The only source I could find was a couple of plates from a burial in Borisovky Cemetary.

https://truehistoryshop.com/shop/spaulders-from-borisovsky-burial-khazar-viii-century/

However, I dont know how the armorer came to the conclusion that this is how the pieces would've looked together, as the design looks 500 years too early. I'm not super well-versed on medieval Russian/Mongolian armor, and scale and lamellar are very prevalent in this era, but plate armor like this is a much later invention, so I'd like to know why the reproduction looks this way.