Yes, hundreds of thousands of people have ported numbers into Google Voice and used the numbers on OBiTALK devices.
However, Google Voice does not port in from landline service providers; only from mobile carriers. You'd have to first port your number to a mobile carrier, wait a week for everything to successfully start working on that carrier, and then port the now-mobile number to Google Voice. If you want to do this, I recommend porting into either T-Mobile Prepaid or AT&T Prepaid. Do NOT use one of the cheapo third party providers like H20, Lycamobile, Consumer Cellular, etc.
You won't have to reset your device, unless you want to, just for OCD completeness. You can simply delete the Service Provider (SP1--SP4) on your device, and then configure that SP for Google Voice.
Reminder: Google voice cannot make emergency 911 calls. You must subscribe to 911 service from a VoIP service provider like Callcentric.