Do I need to act on this warning from apt when installing grub?

[Chris Green]

When doing a routine update of one of my systems recently I got the
following sequence of messages from apt:-

    The following packages will be upgraded:
      grub-efi-amd64-bin grub-efi-amd64-signed
    2 to upgrade, 0 to newly install, 0 to remove and 3 not to upgrade.
    Need to get 1,263 kB of archives.
    After this operation, 9,216 B of additional disk space will be used.
    Do you want to continue? [Y/n] y
    Get:1 http://gb.archive.ubuntu.com/ubuntu kinetic-updates/main amd64
    grub-efi-amd64-signed amd64 1.186+2.06-2ubuntu13 [525 kB]
    Get:2 http://gb.archive.ubuntu.com/ubuntu kinetic-updates/main amd64
    grub-efi-amd64-bin amd64 2.06-2ubuntu13 [738 kB]
    Fetched 1,263 kB in 0s (5,140 kB/s)         
    (Reading database ... 200199 files and directories currently installed.)
    Preparing to unpack
    .../grub-efi-amd64-signed_1.186+2.06-2ubuntu13_amd64.deb ...
    Unpacking grub-efi-amd64-signed (1.186+2.06-2ubuntu13) over
    (1.185+2.06-2ubuntu12) ...
    Preparing to unpack .../grub-efi-amd64-bin_2.06-2ubuntu13_amd64.deb ...
    Unpacking grub-efi-amd64-bin (2.06-2ubuntu13) over (2.06-2ubuntu12) ...
    Setting up grub-efi-amd64-bin (2.06-2ubuntu13) ...
    Setting up grub-efi-amd64-signed (1.186+2.06-2ubuntu13) ...
    Installing grub to /boot/efi.
    Installing for x86_64-efi platform.
    grub-install: warning: EFI variables cannot be set on this system.
    grub-install: warning: You will have to complete the GRUB setup manually.
    Installation finished. No error reported.

It's an Intel I5 based system and I *think* I'm still running legacy
BIOS rather than EFI.  Do I need to "complete the GRUB setup manually"?
(It may be that I've simply missed similar messages during previous
updates)

The system is headless and fairly inaccessible so I'd prefer to do
anything necessary via an ssh connection if possible, though if
needed I can connect a display, keyboard, etc.

-- 
Chris Green