You are damn right on being overly cautious. But to answer your question, yes GRUB2=1.99. GRUB-legacy is any GRUB version < 0.97 (which is the more common GRUB-legacy version used by the distros). GRUB2 started with version 1.9x with 1.97 being the more popular GRUB2 used by the distros.
Any version <=0.97 is now referred to as GRUB-legacy and any version >=1.9x is now referred to as GRUB2 to differentiate between it and GRUB-legacy.
The first version of Sabayon I used was 5.5 and it had GRUB2 by default. Sabayon 7 uses 1.99 also. It follows that Sabayon 8 which I'm now hearing about would certainly use GRUB2 v1.99.
Of course you can verify this by looking for a menu.lst or grub.conf file. These only exists for GRUB-legacy. Again, GRUB2 uses the files I mentioned in my first post.
You can always generate a new boot script without touching your existing one with:
sudo grub-mkconfig -o ~/Documents/mygrub.cfg
You can then inspect this file to verify for yourself.
would give you the info pages for GRUB2.
While most distros install GRUB2 to /boot/grub, some distros such as Fedora and openSUSE uses GRUB-legacy by default, and so places it's GRUB2 files in /boot/grub2. They have also renamed some of the GRUB2 script such as grub-mkconfig and grub-install to grub2-mkconfig and grub2-install.