You might have an additional spot for a numeral in that serial #, but all said in the condition (80-85%), you didn't mention if it looked to be original or at least era stocks, I would say their asking price is way too high for me. IF this were to be in my sphere, $400 would be the top end and that would be under inspection. It's likely an early 60's gun, but if things aren't correct, the price wouldn't be worth more than that to me. Everything original, then $400 would be the low-end in this part of the woods. Offer your amount and see what the response is, but try to get a better look and ask if they'll pull the stocks to see if they match the gun. Good luck!