Packs question

SDS

Someone asked if packs can expire in another post and it got me thinking......

If you get a pack in your inventory, do you think the cards are going to be the same if you open it then or wait a few days?

Like I know if you are 11-0 in BR and you wait for the new rewards to drop before you win your 12th game; you can get to choose those players in your Flawless pack

But what about other packs?

Like if you have a Show Pack and you opened it three days after getting it and the last card is a Diamond. Do you think that last card was always going to be a Diamond no matter when you opened it?

And how about the Bronze and Silver player packs you get from the TA path.

Says you received an AL East pack a few weeks back and you opened it and one of the Silvers was Hunter Renfroe.

If you got that pack in your inventory PRIOR to him going Gold, and opened it after the update, then that Renfroe would've been replaced with another Silver?

Or are they just random and it doesn't matter when you open them?

SDS

Randomly generated at time of opening.