Today rms has released a PS3 Model Detection
Currently the PS3 homebrew app supports both 3.41 and 3.55 systems in addition to Waninkoko 3.55 PS3 Custom Firmware.
Download: PS3 Model Detection PKG for 3.41 FW / PS3 Model Detection PKG for 3.55 FW / PS3 Model Detection PKG for 3.55 Waninkoko CFW
To quote: "Have you ever wondered what specific version of hardware was inside of your PS3?
Well, a dev by the name of rms, has created a PS3 app that identifies exactly that.
The app, appropriately called PS3 Model Detection, will tell you your PS3's System Target ID, Motherboard Revision, and BD-Laser Revision." for determining the PlayStation 3 model so that, among other things, users can see if their console is supported by the various PS3 (CFW) updates available.