Custom theme being prompted for update because of similarly named theme

I've got a custom made theme named "Discovery 2014" on my site and it keeps getting flagged for an update because of a free theme named "Discovery" available via the theme repository. Definitely not my theme, of course. Is there anyway to disable this? I was thinking I might just crank up the version number to like 30 or something that the public theme will never reach. But is there a better or more proper way?

I could always re-name the theme (and going forward I will be using more uniquely identifiable names for themes), but then I'll have to set a ton of stuff back up again, won't I?