YAMAHA XS400 / 500 CARBURETORS ?? Unknown We think just aren't sure read description

I purchased as unknown mikuni carburetors believing that they would fit an XS400 or 500. I do believe they will but I am not 100% sure and I do not have anything to test them on, so please be sure to look at the pictures and compare to your carbs. It is possible that they are for something else completely. Some of the screws on top are stripped and will need to be drilled out. One slide moves freely and the other moves with some resistance. I cant locate any part numbers on the carbs. Please look closely at pictures and as all questions prior to purchase.