2007 ec250 cylinder markings
 

Just curious if this is factory markings on the back of my cylinder or has someone been playing with this one? I haven't pulled the head to measure the bore as of yet.

If it's hard to see there is 285 stamped rear center of the cylinder twice (one over the other). There is also other stampings on the right side that I would guess are factory, but these looked different to me.

That's a 250 A piston stamp they have A/B/C pistons

There is 285 stamped besides the "A". Is that normal?? I know about the a, b, and c sizing.