All You need is to call in terminal this:
grep Revision /proc/cpuinfo
After You get something like this:
Revision : a22082
Go to page https://www.raspberrypi.org/documentation/hardware/raspberrypi/revision-codes/README.md
and search it in text.
Below is a list of information dated as of 08/02/2019 :
| Code | Model | Revision | RAM | Manufacturer |
|---|---|---|---|---|
| 900021 | A+ | 1.1 | 512 MB | Sony UK |
| 900032 | B+ | 1.2 | 512 MB | Sony UK |
| 900092 | Zero | 1.2 | 512 MB | Sony UK |
| 900093 | Zero | 1.3 | 512 MB | Sony UK |
| 9000c1 | Zero W | 1.1 | 512 MB | Sony UK |
| 9020e0 | 3A+ | 1.0 | 512 MB | Sony UK |
| 920092 | Zero | 1.2 | 512 MB | Embest |
| 920093 | Zero | 1.3 | 512 MB | Embest |
| a01040 | 2B | 1.0 | 1 GB | Sony UK |
| a01041 | 2B | 1.1 | 1 GB | Sony UK |
| a02082 | 3B | 1.2 | 1 GB | Sony UK |
| a020a0 | CM3 | 1.0 | 1 GB | Sony UK |
| a020d3 | 3B+ | 1.3 | 1 GB | Sony UK |
| a21041 | 2B | 1.1 | 1 GB | Embest |
| a22042 | 2B (with BCM2837) | 1.2 | 1 GB | Embest |
| a22082 | 3B | 1.2 | 1 GB | Embest |
| a220a0 | CM3 | 1.0 | 1 GB | Embest |
| a32082 | 3B | 1.2 | 1 GB | Sony Japan |
| a52082 | 3B | 1.2 | 1 GB | Stadium |
| a02100 | CM3+ | 1.0 | 1 GB | Sony UK |