Most likely not. The FW16s shipped with LM were pre-orders. The manufacturing process switched to PTM7958 during the last few pre-order batches, if memory serves.
To be certain, check your FW16’s serial number:
[source]
or
sudo hwinfo --bios
or perhaps
sudo dmidecode -t chassis
[source]
If the 11th, 12th and 13th digits are less than 444, the machine was shipped with liquid metal; greater than 444, it shipped with PTM.
Early Framework Laptop 16 devices (serial numbers where the 11th, 12th and 13th digits are less than 444) used liquid metal thermal interface material
[source]