Looking at the registrations I cannot help but wonder if a simple way to change the trade dress would be to remove the outer housing, which in no way affects performance, only the appearance. And Airsoft toys are not firearms so the registration should not cover the item if they are sold as airsoft only.
by outer housing I am refering to this part on the outside that is seperate from the scope. http://thecounterfeitreport.com/uploads/validate_image/1054_1353706968_large.jpg
For trademark law purposes I think it's indisputable that Airsoft guns are firearms. As for trying to "design around" the 551 scope trade dress you need to speak with your own trademark attorney.
ok, thank you. I can certainly see why airsoft would appear to be firearms since trademark is about image.