How to find out whether NVRAM was reset?
Doesn't appear to be a direct way to do this. Part of the problem is that your changes to the NVRAM, if you were to clear it (nvram -c), will not take effect until after a reboot.

You could try this method which will perform a side-by-side diff of the contents of NVRAM prior to running a nvram -c.

For example:

$ sdiff &lt;(nvram -xp) &lt;(nvram -c &amp;&gt; /dev/null; nvram -xp) | less


If there's any changes you should see lines with vertical bars (|) which will denote lines that changed. Content on the left side will be your before and content on the right will be your after.

References


How to View &amp; Clear the Mac NVRAM Contents from Terminal in Mac OS X