Yes, as you suspected the D10SZ has a solid wood top and laminate sides and back, in this case Zebrawood. Washburn released a few "rare-woods" models and IIRC this was one of them.
It's not a bad axe...the D10S models are highly respected around here for their value. They were well made guitars, but did not come with bone or Tusq saddle or nut from the factory, so most likely yours are still the plastic saddle and nut from the factory. Having said that, replacing the saddle is the single most recommended upgrade we see here on the forum, and some people replace the nut at the same time they replace the saddle...but not most, because the nut replacement is much more expensive (it requires specialized files to get the slots right and most often is a job left to a luthier) and the majority of the tonal improvement comes from the saddle, which is more of a DIY project. You can check them with a hot sewing needle...get the tip red hot and poke the side of the saddle with the hot needle and if it's plastic the needle will melt its way into the saddle, if it's bone it won't. Tusq...well, I'm not sure about that, but Tusq has been a popular recommendation around here, too.
From the serial number, I think you're right about the guitar being made in 2005.
We don't see many zebrawood models around here....could you post up some photos?