given is this logcheck rule:
^\w{3} [ :[:digit:]]{11} [._[:alnum:]-]+ systemd-logind\[[[:digit:]]+\]: New session [[:digit:]]+ of user [^[:space:]]+\.$
and this log entry:
Mar 19 09:16:09 horst kernel: [3257039.867032] <38>systemd-logind[193047]: New session 24987 of user icinga.
These don't seem to match, unfortunately I cannot find a matching (sic) rule for the <38> thing. And yes, this seems to be a static number.