Washburn has a sordid history regarding serial numbers...some are 4 characters long, some 5, some 6, might even be some 7 character serial numbers...we do have a group of experts who can positively identify some information from the serial numbers, so if I am wrong on some of what I will tell you, I hope they'll come on and correct me.
From your serial number I can tell (I think) that your guitar was made in Samick, Indonesia (that's the "SI" part of the serial number), and is most likely a 2003 build (the "03" MIGHT mean 2003, but it could also mean 2000, depending on what sequencing system Washburn was using at the time)...for some serial numbers the first number helps pin the year, for some longer serial numbers it's the first two digits...I'll hope our experts chime in.
The Delta King is a product of the parent company of Washburn, but it is an Oscar Schmidt product. Oscar Schmidt is Washburn's entry level line of instruments, perhaps they are best known for their autoharps, but they produce a wide variety of instruments, including hollow body jazz guitars like your Delta King. When I say OS is the "entry level line", I don't want you to think that's a bad thing, the OS line is generally well made and are priced quite reasonably, they may just not have all the bells and whistles that a Washburn has.
That's what little I can tell from the info you gave...have you tried the search function? I did and came up with 3 pages of hits...LOTS out there for Oscar Schmidt Delta King. The search function is on the light grey bar at the top of the page right below the word "Washburn".
We have a saying 'round here....pics or it didn't happen! Can you post pics? You'll need a photo hosting website, like Photobucket, and once you upload your photos onto the photo hosting site you just copy the IMG code and paste it into the body of your post. Like magic your photo will appear in your post and we'll all be able to see it..