Numbers on pistons

[game]

Hi guys wondering if someone could help identify these markings

My mate has asked me to check what pistons he has in his car as previous owner had told him they are forged the only markings he can see when he checked them out are 99600 x0.50

Any info would be good, I am assuming this is not a part number

[p0630034]

What car/engine is it?

Ross Pistons have a piston with part number 99600, think its for a pontiac 455

[game]

The car is a s14 and engine is from a s15

[Aleo24]

Can he pull the sump and check underneath. Most manufacturers have their symbols underneath cp etc.i pulled a block which looked like stock pistons up top but were cp's