It's more than likely a Metal Halide. Interior High bay lights are generally MH because that spectrum is easier on the peoples eyes who work under them. HPS is more commonly used as exterior illumination.
Dont let anyone tell you that MH is wrong for flower. It MIGHT not be OPTIMAL, and that school of thought is being reconsidered, but it certainly has done well by me and a whole lot of others.
If this is your first grow, you'll be just fine with MH. Try and concentrtae on just getting all of your girls across the finish line. A whole lot of people really over engineer this. I know I did, I killed off the majority of my first crop and wasted alot of money in the process. Not to mention the added stress of worrying about every little "hangnail" the plants displayed. Keep at it, it's a learning process.
There is a lot of good advise and knowledge here, but you gotta sort thru it all and find what works for you.
