Coauthors field in fanfiction_stories

I'm not sure if this is exactly a bug or not.  New installs shouldn't have this happen, it's only upgrades.  Particularly I think from 3.4 to 3.5 versions.  It's not something I really need help with, either, but it probably is affecting others.

So, looking at install/install.php, I find this for the creation of a field in fanfiction_stories.

`coauthors` varchar(50) NOT NULL default '0',

That's what it's meant to be, but on my two sites that have been upgraded from 3.4.3, the field is actually null with no default.  Not such a huge deal, until the upgrade script runs this:

dbquery("UPDATE ".TABLEPREFIX."fanfiction_stories SET coauthors = '1' WHERE coauthors != '0'");

Now at my live site I have 528 instances of 1 in that field (out of 1939 stories). There are only two stories with a coauthor, because I've only ever had it turned on for about a month, then turned it off again. I think what happened is it turned blanks to 1s.

This doesn't actually cause any errors or anything, but the future might change the way that works.  I'm going to write a query to fix it since I know which stories are supposed to have the 1. I just wanted to post in case other people find the same thing.

I looked through update.php and couldn't find anything to change the settings for that field, so I don't think it's a case of it not running properly (though I could have missed it). I guess when that field was first created that's how it was supposed to be set?  It just never got changed?