Lost router admin password (plastic tab)

[#1]

I've lost the little bit of plastic with the admin and wireless passwords.

If I do a factory reset will this allow me to setup a new admin password or just reset it to the current one which I don't know?  I've also see posts where the serial number might work as the password, I'll probably give that a try if the response here is slow.

[#2]

A factory reset will not help, it will reset to that on your missing label. The serial number route only applies to old Technicolor routers. Which router do you have?

[#3]

Thanks for the reply.

I got lucky.  In addition to putting the default password on the plastic tab which I lost, it's ALSO written under the router next to the serial number I was hoping might work as a password, so I found it during my search