It’s hard to say how many average moviegoers would notice that the spikes from Godzilla’s return to American cinema in 2014 don’t perfectly match the ones he has in Godzilla: King of the Monsters, but the fact that Dougherty even thought to make these tweaks shows just how much of a fan of the Godzilla franchise he is, specifically the first movie, as he mentioned earlier in his interview with Tamashii JP (via GORMARU).
For Michael Dougherty, that was doing something as simple as making those back spikes look closer to their original design.
When you have a franchise that’s been around for as long as Godzilla’s, it’s nice if there are opportunities to honor/pay homage to the earlier entries, even if they don’t exist in the same current continuity.