From the above you can see that you are running FreeBSD version 5.2.1-RELEASE with security patch p8. You can also determine that your system is booted up on MY_KERNEL_1 which is the kernel configuration you are using. If you haven't built a custom kernel, it'll say GENERIC.
Last but not least, you will see that your system is running on the i386 architecture.
There are three main branches of FreeBSD, they are : 4.x branch 5.x branch 6-CURRENT branch