Hi Marcos! I don't fully understand your question, but I think you're asking if
uptime.getlastreset can give you the "Watchdog" reset reason when the hardware watchdog indeed is the cause of the last reset? If this is what you're asking, then the answer is yes.
You can actually test this by calling the
scout.reboot command, which will set the watchdog timer to 15ms, and then go into an infinite loop. (It's the safest way we found to do a runtime-based reboot, according to Atmel.)