I agree in a general sense
@Mike66Chryslers , but note that there soldered unions in the dash harness, which the factory calls welds. Perhaps there's a difference. Regardless, they're done without flux, which is the problem, since it can contain acid, and it can make for problems down the road (pun intended). Soldering at a crimp connection is generally a no-no, due to the flux issue.
I agree that wire nuts such as the "pinch and snap" type are no good, but a proper fully insulated wiring connector such as a small terminal block with cap is OK, in my thinking, and hence, done right, a good nut and bolt union with proper ring ternimals and lockwashers under nuts, with the whole shebang properly insulted should suffice.
My wagon had two such "previous owner" unions under the dash, and I've owned it 25 years, and who knows how long they'd been there before, but they were properly done and hadn't budged or corroded.