No side-slotted pistons in 3.4 liter year 1958

Recently I’ve disassembled my Jag motor, 3.4 Litre (aka Mk1, 8:1 comp.).
I noticed that pistons lack the vertical side slot (relief ?).
I’m hoping to reuse them in assembly. Is lack of slots a problem ?

Nope! Gazillions of pistons do find w/0 them. Pistons on Jags were fitted pretty tightly, and the slotting helped with that.