brake piston
 

Hi I'm new to this forum.
I've had an'84 xt600z (Italian import) for a couple of years, and I'm just doing it up.
I've just bought a new front brake caliper piston and seal kit from my local dealer, but it looks different to the one on the bike. This one has smooth sides, whereas the original has a square bottomed groove approx 5mm from the open end of the piston, and a larger dust seal. Can anyone tell me if the two are compatible.
Many thanks David