In considering whether a different key will be useful to unlock any given shutter, you need to consider how these actually work (this is true of my 2013 model at least). The tl;dr version is that ANY key can close it but only the RIGHT key can open it.
To close it, the key is pushing the shutter closed against a spring into the latch. If the latch holds, when the key is withdrawn the shutter stays closed. Closing it, the latch stays closed when the key is pushed in because the magnets in the key are inverted (repelling those in the latch activator instead of attracting them) and the cutout in the key us inverted so even if the magnets were right the latch is being held closed. (this feature allows inverting the magnets in the key to be a valid new combination - rather than allowing a wrong key to open it just by being inserted in the "close" orientation) All that is needed to close it is to insert a key in the "close" orientation and push it til it clicks - ANY shutter key will work.
To open it, you need three things to be true:
1: The magnet pattern in the key matches that in the latch.
2: the key is inserted with the cutout uppermost
3: the key is inserted far enough that you can feel the spring pressure, allowing the magnetic tumblers to release and open the latch.
If all of these three things happen the latch releases and as you withdraw the key the spring opens the shutter. You need the right key for your lock to satisfy #1, there are several numbered variants. You need the key to be in the right orientation (silver side up) to satisfy #2. #3 is just a matter of pushing it far enough before withdrawing it. Show me a guy on this forum that cant do that
When taking delivery of a new bike, the key ring has a tab on it giving the right security shutter key number, with that you can order a new replacement that matches your lock from Kymco. If you dont have a record of the number they might be able to look up the right one from the VIN. If not then you're SOL.