Thanks for the reply. I was curious about the fact that Trainer Deck A/B cards have shadows on their frames when they were technically released a bit before 1st ed./shadowless. If so, it seems the designs went shadow (trainer deck A/B) > no shadow (1st/shadowless) > shadow (unlimited)?
Or maybe they had already switched to shadows when it was general release time, but had printed the first runs shadowless already so just distributed them anyways?
(random internet examples)
That’s interesting! They did have the shadows. So does Japanese. Idk why wotc changed the design from Japanese
Yes sorry what I meant to round out by saying is that the revised design was probably occurring simultaneously with the actual release and it just so happened that the Trainer Decks used that design.
“Alright! I’m back from Japan! How’re things in printing, Jim?” 
“Hey, Joe! We got the first print run done. The cards are allocated for the experimental 1st Edition stamps, and”
"JIM! Wha- Where’s the shadow around the illustration box?! The Japanese versions all have shadows around the box! …Like this! Ours are ‘shadowless’! "
“Oh damn… Well, we haven’t started the second run yet. We can fix.”
“While we’re at it, who put the red marker on pikachu’s cheeks?” 
(Yes, I know that the red cheek change was removed before the end of shadowless print run. Are there any yellow cheeked 1st Edition?)
The earliest shadowless theme decks have the weirdest shadowless exclusive errors, like ghost Pikachu and No Damage Ninetales. There isn’t much indication that they fixed problems that 1st edition had with unlimited shadowless cards… So it’s possible some shadowless cards were actually printed before some 1st edition cards. Especially if shadowless cards seem to have more errors than 1st edition ones.
It isn’t known if there is more 1st edition or shadowless cards, but there is likely less shadowless cards in good condition because those were the ones kids opened and played with. One reason why a mint set of shadowless might actually be rarer.
