Got a brand new DuraAce 9100 crankset here with a plastic preload cap - I've just checked. You can buy alloy ones aftermarket with an allen key fitting rather than the odd Shimano splined fitting, but I'm not aware of any Shimano cranks with alloy preload caps.
BTW, the screenshots posted above look nothing like any version of LFGSS I've ever seen.
Got a brand new DuraAce 9100 crankset here with a plastic preload cap - I've just checked. You can buy alloy ones aftermarket with an allen key fitting rather than the odd Shimano splined fitting, but I'm not aware of any Shimano cranks with alloy preload caps.
BTW, the screenshots posted above look nothing like any version of LFGSS I've ever seen.