Value is impossible to estimate without seeing it and giving it very close examination. But they are usually not worth more than a couple of hundreds dollars at best , if you can find someone who wants it at your price. But it may be something else,we don't know what it really is, we haven't seen it. The Crowns could be proof marks, the style of crown and if there are letters or other marks beside or around it. These can indicate if it is Belgian, French, German or British made or imported to there, then brought back here. Usually every firearm being imported to those countries has to be proofed , then if it leaves you can have a North American gun with a european proof mark which can confuse things a little.