NO!! Although earlier models with dw designation (e.g. M476dw) had duplex scan!
So I had to return the HP M479dw and then buy the M479fdw. This one, M479fdw, has the "duplex scan" - as well as duplex print - and unnecessarily still has the FAX connectivity :-(
And if you take both models here in the comparison, then you would also see it, actually - but I did not succeed.
But now I am satisfied with the M479fdw and will take a closer look next time I buy one :-)

Thank you Thom_Stahl👍🏻

we have just bought the M479dw and tested it for duplex. it works. it has no fax connection.