Carb ID help and/or info

OK.....is there a tab or number or anything on the carbs that tells me what I got? I think carb bank was swapped by previous owner years ago....no way to know tho...
With the off-season upon us, I wanna go thru the carbs and check everything, but i got to know what i got, first. Any/all help appreciated.
77 1000A1.
Thanks...

explain the carbs. how many screws hold the top lid on? what does the bowl and drain screw look like on the bottom? this will identify the carbs.