try asking Ubisoft Support , this forum is not UBISOFT support
as to your question about Steam .. the only way to get the Steam version of the game is Buy the game on Steam
the retail boxed DVD version is Uplay only (no steam involved )
you could try downloading the latest version of Uplay here https://uplay.ubi.com
create or login to a uplay account that you already have (if you have a uplay account from installing a previous Uplay game )
then select activate product and input your Far Cry 4 Key
the version that comes on DVD is outdated so no matter what you'll have to Download all of the updates via Uplay anyway ..and some were quite large
and i do recall some saying that when they tried to install and update the game from the DVD version it re downloaded the whole game anyway
try giving UBI support a call on the Phone and ask them first would be what i would suggest if you don't wanna try the above
you can reach them here
You can also call them on the phone during regular support hours <--(BEST OPTION)
You can find phone number information here: https://support.ubi.com/en-US/FAQ/60...0000000eiChCAI
You can also try to contact them via social media.
Facebook: https://www.facebook.com/UbisoftSupport
Twitter: https://twitter.com/ubisoftsupport
Good luck!