I don't claim to know anything about the guts of Perl, but in an assignment from an array to a hash, how the hash stores key value pairs should be immaterial. What is material is how Perl scans the array for elements and whether those elements are stored in the array in deterministic ashion. As far as I can tell, they are.

Testing, I get:

#!/usr/bin/perl
use warnings;
use strict;

my @array = ( 'A', 1, 'B', 2, 'C', 3, 'A', 4 );
my %hash = @array;
for (sort keys %hash ) {
    print "$_ => $hash{$_}\n";
}
print "\n";
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And the output is (for Active State Perl 5.8.8):

C:\Code>perl array-hash-order.pl
A => 4
B => 2
C => 3
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