Here's my stab at it:

#!/usr/bin/perl

use strict;
use warnings;
use Tk;
require Tk::LabFrame;
require Tk::LabEntry;

my $mw = MainWindow->new;
$mw->geometry("150x80");
#$mw->optionAdd( "LabFrame.font", "helvb12" );

my $canvas_total = "Label Test";
my $le_t_text    = "LabFrame Test";
my $le           = $mw->LabEntry(
    -textvariable  => \$canvas_total,
    -labelVariable => \$le_t_text,
    -labelPack     => [ -anchor => "center" ]
);
$le->pack( -expand => 1, -fill => "y" );

#print STDERR $le->optionGet( "font", ref $le ), "\n";

MainLoop;
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I used the labelpack example from the source as a starting point. Note that I commented out the optionAdd because it didn't make any difference. Also the print statement.