I'm on a mac and my 7800DX does not even give me the option of selecting 2-sided, it just automatically does it. I'm on Sierra on my iMac. Is there a generic driver or updated driver I can install to get my option back?
Since you don't have the option you already are using a generic driver. If you were not before and are now then you did an update to the Mac and they removed the Xerox driver and replaced it with the Generic PS Driver.
Install the Xerox driver and there is no way you won't have the option
I updated to the latest driver as requested and the option of printed 2 sided is still not there. I have the 7800 set as my default. I use QuarkXpress and InDesign. Neither are showing me the option of printing 2 sided.
Try looking at the driver settings by selecting Xerox Features instead of the Layout that is provided by Apple.
And in the right screen, that is Indesigns interface, click on Printer to look at the actual print driver and do the same as in the screenshot above.