Sure. The keys of the hash are strings, the values are scalars. And the values of the scalars are copied, even if the value is just a reference. It's the same as this:

my $x = 999;
my $r1 = \$x;
my $r2 = $r1;
print "\$r1=$r1\t\$r2=$r2\t\$\$r1=$$r1\t\$\$r2=$$r2\n";
$x = 111;
print "\$r1=$r1\t\$r2=$r2\t\$\$r1=$$r1\t\$\$r2=$$r2\n";
${$r1} = 555;
print "\$r1=$r1\t\$r2=$r2\t\$\$r1=$$r1\t\$\$r2=$$r2\n";
${$r1} = 777;
print "\$r1=$r1\t\$r2=$r2\t\$\$r1=$$r1\t\$\$r2=$$r2\n";
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