[CentOS] using lpadmin to add printers in CentOS 7 (v. CentOS 6)

Fri Aug 24 01:09:33 UTC 2018
Zube <Zube at stat.colostate.edu>

In CentOS 6, I could do:

lpinfo -m

then pick the model I want and put it as the option to -m in lpadmin
(line wrapped):

/usr/sbin/lpadmin -p printer -o printer-is-shared=false -o Duplex=None
-o Resolution=600dpi -m 'gutenprint.5.2://pcl-g_5e/expert Generic
PCL 5e Printer - CUPS+Gutenprint v5.2.5' -v 'socket://mydomain.edu'

Alas, in CentOS 7, no matter what I do, I always get:

Unable to copy PPD file!

and the error in the cups error log:

Returning IPP server-error-internal-error for CUPS-Add-Modify-Printer (ipp://localhost:631/printers/printer) from localhost
Bad ppd-name "gutenprint.5.2://pcl-g_5e/simple Generic PCL 5e Printer - CUPS+Gutenprint v5.2.9 Simplified" (-6)!
copy_model: empty PPD file

I assumed this was due to the newer version of cups. 

To make it work (kinda, sorta) the way it used to:

1) mkdir -p /usr/share/cups/model/gutenprint/5.2
2) cups-genppd.5.2
3) lpinfo -m, but choose one that is a file, not a gutenprint.5.2:// URL (?):

/usr/sbin/lpadmin -p printer -o printer-is-shared=false -o Duplex=None
-o Resolution=600dpi -m 'gutenprint/5.2/stp-hp-lj_4250.5.2.ppd.gz'
-v 'socket://mydomain.edu'

And this is fine, but I assume the other way should work as well.
What am I missing?

Thanks for any clues.