Where to report issues regarding the stock-email-app Is
    http://code.google.com/p/android/issues/entry
the right place for bug reports?

My device is a Samsung Galaxy Note 10.1 LTE 2014 Edition (SM-P605) with it's original shipped OS (Android 4.3).
This depends upon the ROM that you're using.

If its stock, you're stuck, for most OEMs don't allow sending big reports as such.

If its a google device, or any other device running AOSP, then, the link you've posted is appropriate. Be sure to provide as much related and useful info as possible.

If you're running custom ROMs, they'd often provide you with links, so as to where to post bug reports, (most often being the thread itself (assuming that you're using a custom ROM taken from a forum)), which is where you ought to be posting bug reports.