i purchased a used stingray 4-string two days ago. the guys at the shop i bought it from were unsure of the year, said it "might be a '91". is the 5-digit number stamped on the bridge the serial number? that number is 46366. also, the neck plate has four bolts, but i see on the website for the stingray that they are made with a six bolt neckplate. all of the hardware on the bass has the musicman logo stamped into it, and i can't see where any modifications have been made, so i'm curious for any and all identity type info i can get for this bass. it's black w/ white pickguard and rosewood fretboard. THANKS!