Changing Google password / multiple devices

I recently sold a (crappy) android phone on ebay, and I realized that I forgot to wipe the device (it's in the mail). If I change my google password, when the buyer turns on the device, they will be prompted to input the new password, correct?I'm aware that they might be able to read the email already on the device, I just don't want them to be able to send email/messages/etc to people from the device using my account.