macNaughton..first hammerless shotgun

I own this damascus double-barrelled beauty..Missing 2 small 16/32nds screws and 1 leaf spring. I wish to have appraised. This particular model was made for a Mr. K.ff.BriIIhirs. imported by Ware BROTHERS GUN STORE IN SPOKANE WASHINGTON. WON GOLD MEDAL 1881 MELBOURNE EXIB. THANKS