Yes! You can upgrade your non-drive side (left side) powermeter to a dual by purchasing a factory install for the drive side (right side) only. We do not need you to send in the non-drive side to install the new powermeter however, the chainrings must be sent.
If your intent is to upgrade in the future, you will first want to check compatibility prior to purchasing to ensure we offer the drive side install on your specific crank: Crank Compatibility Finder
When upgrading to a dual powermeter with a right side installation, you only need to send us your right crank for installation. The new right side powermeter will seamlessly pair with your existing left side powermeter in the 4iiii App to give you the full functionality and accuracy of the dual powermeter.