Question about my Tobias 5 string bass

I bought a Tobias 5 string bass from a music store in Raleigh, NC in the mid 90s. I didn't really know much about Tobias. I just liked the way the bass played and thought it sounded good. Years later, I'm trying to figure out exactly what I have. It is a 5 string with a bolt-on neck. Everything I've seen leads me to believe it is a Killer B. The issue I have is the serial number stamped on the neck. The serial number is 1306153. This doesn't match any serial numbers I have seen on any sites or forums. Any help would be greatly appreciated.