Hi Todd,
Unfortunately that is the only info you can get about a Customer in Order Printer at the moment. You can see exactly what is available by just adding {{ customer }} to your template, which results in:
{"email"=>"hello@orderprintertemplates.com", "name"=>"Order Printer Templates", "orders_count"=>1}
This is not only for POS orders, but any order :(
Regards,
Bjorn