Here is how to find the model name, version number and hardware revision of your Raspberry PI
1. Find the 'Revision' value
Open a ssh session and run this command:
$ cat /proc/cpuinfo
Find the value 'Revision'
2. Compare the value with the following table
| Model and PCB Revision | RAM | Hardware Revision Code from cpuinfo |
| Model B Rev 1 | 256MB | 2 |
| Model B Rev 1 ECN0001 (no fuses, D14 removed) | 256MB | 3 |
| Model B Rev 2 | 256MB | 0004 0005 0006 |
| Model A | 256MB | 0007 0008 0009 |
| Model B Rev 2 | 512MB | 000d 000e 000f |
| Model B+ | 512MB | 0010 0013 900032 |
| Compute Module | 512MB | 11 |
| Compute Module | 512MB | 0014 (Embest, China) |
| Model A+ | 256MB | 12 |
| Model A+ | 256MB | 0015 (Embest, China) |
| Model A+ | 512MB | 0015 (Embest, China) |
| Pi 2 Model B v1.1 | 1GB | a01041 (Sony, UK) |
| Pi 2 Model B v1.1 | 1GB | a21041 (Embest, China) |
| Pi 2 Model B v1.2 | 1GB | a22042 |
| Pi Zero v1.2 | 512MB | 900092 |
| Pi Zero v1.3 | 512MB | 900093 |
| Pi Zero W | 512MB | 9000C1 |
| Pi 3 Model B | 1GB | a02082 (Sony, UK) |
| Pi 3 Model B | 1GB | a22082 (Embest, China) |
| Pi 3 Model B+ | 1GB | a020d3 (Sony, UK) |
| Pi 4 | 1GB | a03111 (Sony, UK) |
| Pi 4 | 2GB | b03111 (Sony, UK) |
| Pi 4 | 4GB | c03111 (Sony, UK) |
Source :
https://www.raspberrypi-spy.co.uk/2012/09/checking-your-raspberry-pi-board-version/