A little puzzled about pistons.....

I recently ordered a complete top end kit for my bike so i can do the top end in a month or two. When I received it the gaskets and everything say for 99 RM250, which is what I have but the piston says 00-01 RM250. I've been doing some searching around and I cant figure out if its really the same as my 99 or not. Some sites have piston kits that say 99-00 and others say 00-01. So does anyone know if the pistons are actually the same? All the specs seem to be the same so i was just curious. Oh and it is a PRO X piston part number 19-5200B. Someone please help me, i'm stumped

looks like i got the wrong piston, i needed a domed while the new one is a flat head :bang:

yeah their seeing if they have a piston for me to swap withm we'll see what happens. They include a full top end gasket set as well for free so I'm not that upset, it was good price so if worse comes to worse i'll sell it to someone and get the correct piston elsewhere