Canadian Star Notes?

From 1954 to about 1979-1981 asterisks were used for replacement notes of $1, $2, $5, $10 and $ 20 notes.
From 1975 to about 1981 asterisks were used for $50 and $100 replacement notes.

In 1979 the $20 and $5 replacement notes are designated by the second digit in the serial number
The digit 1 following the first digit 3 of the $5 notes designates a replacement note.
In the $20 denomination the replacement notes can be distinguished by "510" for the CBN company and "516" for the BABN company

Example $5 replacement 31000251926
$20 replacement CBN 51002170046
$20 replacement BABN 51602242559

In 1986 the "BIRD SERIES" replacements can be identified by the third letter in the prefix which would be an "X"

example ARX1604798

After 1990 the Bank of Canada discontinued the use of "IDENTIFIABLE" replacement notes yet collectors and brick searchers eventually discovered ranges of notes that were used as replacements and inserted into sheets or bricks as needed....
They are known by some as modern day replacements, or inserts....
to go a little farther there are sheet replacements and SNR's (Single Note Replacements)