The only way you are going to tell is if you measure the mounting holes on the back of the 43" set you have.
See if they are a fixed 200 mm in spacing.
Your next point of concern is what type of wall you intend to mount the wall bracket too.
If solid brick then fine.
But if a studded, or partition wall with a bracket rated for a 32" Tv and fitting a 43" tv it may rip the bracket of the wall due to the extra weight and lack of enough screw fixings for the wall.