The seller was Focus Memory on Newegg, DIMMs are Rimlance. It arrived quickly via DHL. I'd be a little sketched out to do this if it wasn't registered ECC. The dies appear to be Micron, register IDT, but there is some possibility of soft fraud where they die printed over something. The registers look a little scratched so I wonder if they found some way of recycling DIMMs or even dies. The SPD is their own.

# dmidecode 3.7 # SMBIOS entry point at 0xba970000 Found SMBIOS entry point in EFI, reading table from /dev/mem. SMBIOS 3.3.0 present.

Handle 0x0023, DMI type 16, 23 bytes Physical Memory Array Location: System Board Or Motherboard Use: System Memory Error Correction Type: Multi-bit ECC Maximum Capacity: 1 TiB Error Information Handle: 0x0022 Number Of Devices: 8

Handle 0x0027, DMI type 17, 92 bytes Memory Device Array Handle: 0x0023 Error Information Handle: 0x0026 Total Width: 72 bits Data Width: 64 bits Size: 32 GiB Form Factor: DIMM Set: None Locator: DIMM5 Bank Locator: BANK4 Type: DDR4 Type Detail: Synchronous Registered (Buffered) Speed: 3200 MT/s Manufacturer: Unknown Serial Number: 05A23401 Asset Tag: Not Specified Part Number: RRD25600D4C8K256 Rank: 2 Configured Memory Speed: 3200 MT/s Minimum Voltage: 1.2 V Maximum Voltage: 1.2 V Configured Voltage: 1.2 V Memory Technology: DRAM Memory Operating Mode Capability: Volatile memory Firmware Version: Unknown Module Manufacturer ID: Bank 1, Hex 0x80 Module Product ID: Unknown Memory Subsystem Controller Manufacturer ID: Unknown Memory Subsystem Controller Product ID: Unknown Non-Volatile Size: None Volatile Size: 32 GiB Cache Size: None Logical Size: None ...

Super info, thanks!