Nokia Software Updater for Retail will tell what version your phone is on and it will tell you what's the latest firmware it sees on nokia servers. so for my 1020, i'm on 8.1 Update 1 DP on Lumia Black (xxxx.40000.xxxx.xxxx series) before.. since my country variant already has a Cyan firmware, i decided to run Nokia Software Updater for Retail so i can downgrade to WP8 Lumia Black since i was on developers preview.. upon running it, it shows that the latest firmware for my device is Cyan (xxxx.50009.xxxx.xxxx series) so it is now easier coming from developers preview..
thus countries with Cyan firmware are also downloadable in Navifirm+ if you choose the Nokia Care Suite path which is quite a task to do compared to Nokia Software Updater for Retail which is just a few clicks..
also to answer your question, yes you can use it to check if your country has Cyan firmware, it won't download the firmware right away, so no need to cancel or anything..
good luck on your update