Got the chance to buy three old shotguns today for what I hope was a steal. This is where I need your help. The first is a LeFever nitro special sxs in 16 ga, s/n 1789xx that I would grade around 65%. The second is a Triumph .410 single shot, s/n E975xx that probably grades about 60%. Last but not least a Diamond arms co. 16ga single shot, this one I am unable to read the s/n, but would probably grade around 45-50%. Any ideas on date of manufacture and value would be greatly appreciated. Thanks THR