I am taking apart a newly rebuilt (never run) engine that i recently purchased to check it out and I found that the 4th piston was facing the wrong way when compared to the 3 others (ie the 060 for 60 thou that is stamped on the crowns went 060, 060, 060, 090 for cylinders 1, 2, 3 and 4 respectively when you looked at them in the block from the top).
The rods were all in the correct orientation on the crankshaft as below;

Pistons 1, 2 and 3 have what appear to be a half arrows stamped onto them and these were pointing to the front of the block (oil filter side).
The half arrow on piston 4 was facing the rear of the block
here's a pic of how the 3rd and 4th pistons were oriented when they were installed in the block (pistons 1 and 2 were oriented the same as piston 3);
I was under the impression that the arrows on ALL pistons must face the front so that ALL pistons are in the same orientation?
Can anyone please confirm this as i want to make sure everything is right before i start putting it back together?
Cheers
Dave