I actually do have a modified date for each record. But if it is not needed then I wont worry about it.
Thanks for your input!
I just noticed something else and imagine it will be an issue.
The main site is a wordpress site and this database is totally outside of wordpress. It has the jetpack plugin installed which includes SEO stuff.
According to their website:
Jetpack’s XML sitemap can be accessed at yoursitename.com/sitemap.xml.
Wont that conflict with my new one?