The sunblaze fixtures are identical to the HTG T5s I have - you can pull the reflector off, but the back panel generally holds the tube mounts in place, so I'm not sure if you could remove it.

I've pulled the reflector off so I could mount the T5 unit to a wall, then reinstalled the reflector and run tubes like that.

It wouldn't hurt to pull the reflector off and look inside, I doubt very much that will void your warranty. Cracking the paint around the back panel and the side frame might be a warranty-voider, though, as an obvious sign of user-servicing.