Should the Chieftain MK5 have L23 apfsds

Both the MK3 and MK5 chieftain are woefully underpowered in comparison to the competition at 8.7, however i might have a solution for the mk5. i haven’t found an answer for sure but L23 apfsds was introduced in early 1985 and the mk10 upgrade package wasn’t implemented till at least late 1986. any chance someone has a definitive answer about whether or not the mk5 ever carried L23 apfsds (L23 not L23a1)