yes, assuming you can boot from it into DOS.
don't know, but probably ok, assuming you can boot form it into DOS.
you should, for when things go all dark and stormy.
Most BIOS flash programs, e.g. AWDFLASH, as well as WinFlash have an option to save a copy of the existing BIOS.
If your machine supports WinFlash, use that. This is a Windows app that will allow you to save a copy of existing BIOS and flash a new one.
If not, determine whose BIOS you're running (e.g. Award) and get their BIOS flash program (e.g. AWDFLASH.COM). These will be DOS and require booting (floppy, cd, whatever) into a DOS environment. The flash program and appropriate BIOS should be available at your mobo's support/download site.
Comment
If you simply want a copy of your current BIOS, go to your mobo's download site and download it.
CAUTION
Your questions suggest that you don't have a great deal of experience with flashing a BIOS. If so, no insult intended. If not, you will want to do a lot of reading ... it is not technically difficult at all, but WinFlash and the DOS-based flash programs will enable you to trash your BIOS programming quickly and easily. Again, if you simply want a copy of your current BIOS, go to your mobo's download site and download it.