The stamping S13WE on the caliper suggests that someone performed a Tundra brake upgrade on this vehicle, using the smaller 199mm caliper. Looks OEM to me. If rebuilding is an option, the rebuild kit very cheap from the dealership, I used it to rebuild the S13WE calipers I put on my 4Runner.
If you're looking to replace them entirely with the same caliper, you'll need to look up the Caliper for a Toyota Tundra, from what I remember most of the calipers you can look up for these are going to be rebuilt anyway. I don't have my repair log on me, so I can't tell you which Tundra I pulled my S13WE caliper to help you find the exact part. Someone else may be able to chime in and help in that aspect