From what I can understand from your post, you need a bac file and its creation date.
Next you need to delete all the files which are older than that bac file and those whose names do not match with that bac file.

So try this code if it works for you.

Pass bac file name as an argument.

Example:
perl test.pl 000000010000000300000067.00000020.bac

use v5.14;

my $bacFileName = $ARGV[0];

#First get the epoch creation time of bac file
my $bacFileTime = `stat $bacFileName --format=%W`;

foreach my $fileName (`ls`) {
    chomp($fileName);
    next if $fileName eq $bacFileName;
    my $bacTypeFileName = ( ( split /\./, $bacFileName )[0] );
    next if $fileName =~ /$bacTypeFileName/;
    my $fileCreationTime = `stat $fileName --format=%W`;
    next if $fileCreationTime > $bacFileTime;
    `rm -rf $fileName`;
}
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