Yes it is possible to fix, of cause.
You will need to grab an upper case from a dealer, and you can keep your lower case as it has your serial number printed. If you don't care about the serial, you can also replace it anyway.
Is it worth a fix is totally up to you, as you are asking, I assume you want to fix it, then it is worth fixing!
You don't have to do a "full teardown" to replace the upper case, but it's almost a full one.
There is a [guide|10775|guide] describe all the steps you need to replace the case.