There should be some G&G's available at TAC-09 (not necessarily Frank, but there'll be others there selling similar stuff), and there'll also be several Age Verifiers on hand.
As for your American friends, I don't think they know what they're talking about.
In Canada, many G&G use a transparent, plastic lower receiver for legal reasons. The comment on zinc mechbox is.... Confusing. Since the vast majority of mechboxes are zinc alloy of some sort.
"The Bird of Hermes is My Name, Eating My Wings to Make Me Tame."