Belgium Browning Over/Under

I have a Belgium Browning Over/Under set. It has one stock, two barrels - 410 and 28 ga. I know there are different grades. Is there an easy way to tell what it is by using the serial or something? My father-in-law, who sold them to me (at a good price no matter what grade they are) told me he thought the were a higher grade. It came with a custom case to hold it, I'm guessing that's pretty standard. I'm wanting to know for appraisal/insurance reasons.