If it has a standalone driver it will be rated by input voltage and total load capacity, either watts or amps. Unfortunately, a lot of low-cost LED fixtures don't use discrete/replaceable drivers. Rather, they design the LEDs as an integrated part of a simple driver circuit with everything on a single board.
Honestly, unless it some kind of high-dollar unit, or you've designed it into the room aesthetic, it's faster and easier to get a couple of inexpensive replacement fixtures. I still try to go with fixtures that use Edison-base lamps. That way, when a lamp fails I just screw in another one rather than having to replace the whole fixture.
Have a pic of the fixture? Maybe we can figure something out.
Brad