Just a follow-up. Received the brick I ordered directly from Dell. It is an LA330PM160. Nearly twice what I paid for on Amazon, but no worries or issues. Definitely worth looking up item 332-1432 on the Dell store if you want to avoid any crapshoot. Completely worth the $160 to me.
Edit: Okay, apparently not quite. After a shutdown, I'm unable to boot it up again with the LA330. The 65w boots to bios fine still, so I'm trying to drain and unplug everything for a bit to see if it helps.
I just installed some drivers, so wondering if that could remotely possibly affect it....
Edit 2: Fully draining the brick of power seemed to clear out whatever oddity was going on. It also seems fine after additional reboots and the like.