Well..."new tooling"... I don't know, but...

Here's the Scalemates history for the I-1 kit:

https://www.scalemates.com/kits/minicraft-model-kits-b-38-japan-navy-submarine-i-1-and-i-6--1022829/timeline

It says "new parts" for 2025. Now, that can mean all sorts of things. They could have simply added a small PE fret, or even just changed the decals, and unfortunately the site does not give details. I doubt any sort of actual retooling, but some sort of "refresh" was apparently just recently done to the kit. Some online hobby shops show kit contents, or you might find a review which would show you what changed.

Here's what Scalemates has for the other kit's history:

https://www.scalemates.com/kits/hasegawa-43095-i-361-and-i-171--160212/timeline

Doesn't look like much changed for that.

HTH some