RAY This ecto-containment system that Spengler and I have in mind is going to require a load of bread to capitalize. Where are we going to get the money?
Yes, but I don't think that quote necessarily means Egon and Ray were like, equal partners in the development of the technology. Although according to most sources, Ray either has a degree in Metallurgy or Engineering, so it's not outlandish that he was involved in the nuts and bolts construction.
I had always taken that quote as being Ray as the idea man, paranormal expert/fanatic with Egon being the brains to actually create the tech.
And the rest of the tech is clearly related, so it makes sense to me that Egon was (mostly) the theories and prototyping guy of the pair and Ray was the fabricator, so while he might struggle to come up with any new technology unrelated to stuff that they've built before, he's fully capable of fabricating new copies or even versions of established technology?
It's reasonable, and actually makes sense given how the "new" technology looks... the new proton packs are incredibly similar to Spengler's Afterlife-modified pack (because, by and large, they're modified Haslab Afterlife Spengler packs...), down to the exposed wires, ribbon cables, etc.
So yeah it does very much seem like they can replicate the tech almost exactly with some tweaks, but building NEW stuff may be currently out of reach. Even Lucky's hand-blaster thing was just a modified neutrona wand (I want to get a better look at that to see where it's getting its power from).
On an unrelated note, part of why I want to get a look at the hand blaster is... I want to build one. I do GB cosplay, and I have two spare neutrona wands I could cannibalize for it. I'm also considering doing some light modifications to my proton pack, right now it's straight '84 (I weathered it more, added some small things), with the Afterlife Spengler wand (soon i'm going to get some grips 3D printed to make it an '84 wand). I kind of want my gear to be a multi-era hybrid combining GB1/2, the video game, and the new movies. I've had the new radio they use since the first trailer, mounted on the pack strap like the video game. I want to add the slime container from the game on the side. I might just do the "caution tape" style side panel from Frozen Empire. I don't want to do the new yellow support strut.