@David's comment led me on a bit of a goose chase eventually finding this link: Add line numbers to source code in vim
For my purposes what I needed was not necessarily a persistent numbering, but just a temporary one. Quickly insert/remove line numbers and then resort to the standard numbering. For this case, I hadn't thought of simply inserting then deleting my own line numbering. The below works well. And the possibilities are endless for numbering (see for example https://stackoverflow.com/a/252774/2816571)
%!awk '{print NR,$0}'
For a native vi solution to adding numbers then (from https://stackoverflow.com/a/253041/2816571) the below will insert line numbers then the space character:
:%s/^/\=line('.').' '/
Then (thanks Lance) https://stackoverflow.com/a/4674574/2816571 when done with the numbering, do something like this, but you might need to tweak the search pattern depending if you put a space, comma separator
:%s/^[0-9]* //
If there is something I am missing inside vim that can do the persistent 0 based numbering, please let me know.