What model of Librem are you talking about? What HWIDs are you talking about?
If you are talking about, say, Librem 5 and IMEI then
a) you won’t necessarily be able to do that because the modem is still blackbox and may prevent or not be able to change the IMEI
b) it is illegal to change the IMEI in some countries
If you are talking about any model of Librem and a MAC address (only WiFi, not ethernet, at the current time) then
a) yes, no drama to change and happens automatically in some cases
b) why would this be needed given that the MAC address would not be exposed outside the LAN by normal networking protocols? e.g. Spamhaus or your ISP would not see the MAC address via normal networking protocols
c) however you definitely need WiFi MAC address randomisation for portable devices when not associated with a WAP
d) and for the Librem 5 you need BT address randomisation