trying to match Mikuni BS34 on a xs400

Hey guys iv been working on this old xs400 that has Mikuni BS34's. So im having a good friend get the bike in running shape and he is having some trouble with the carbs. From everything that i have seen i have 2 Mikuni BS34's on my bike but one looks like it is stock to the bike and one looks like it is off a later model xs400. They are almost identical and the only thing that i have seen that differs between the two carbs is the way the float valve seat is held to the carb. So here is the question Do i need to get a new set of matching carbs or will the two carbs work on the bike?

Here is a pic of the carbs The circled one is the one that looks to be off a newer bike I believe off a 82 xs400





Another thing is the fuel air screw on top of the carbs



Thanks for all the help guys this forum is the only thing that has gotten me this far!

Ok well i found a set of cheep Mikuni BS34's that came off a 1980 xs650 for $40 from a friend of my dads. Every thing iv read has said that they will work on my bike but im still crossing my fingers that they will fit. I will let yall know if they do!