Can I take the liberty of running 1.10.2 directly after 1.8.3 for another website?

I was running 1.7.4 on one of my sites and I updated directly. Worked fine.
Yeah, me too on a couple sites. If you're upgrading GOOGLE MERCHANT FEEDER, then no, I wouldn't uninstall fisrt.

But if you're running GOOGLE BASE (FROOGLE) FEEDER, I would uninstall. Then install GOOGLE MERCHANT FEEDER.

But I would take a couple screenshots of the configuration first so I don't have to look up all the settings again.