I don't believe that any reputable builder sets out to produce 'duds'. I believe they intend every single instrument to be top quality, however they are built by human beings and they use organic materials, and the performance of both these elements may vary slightly. I may be lucky, but I don't recall ever hearing a Martin that I'd describe as a 'dud' - the worst I've heard I'd describe as 'good', some as 'excellent', and a few as 'stellar'. And I reckon I'd do the same if I was rating a selection of any builders' instruments. Anything built by humans, and especially built from organic materials, will be subject to some variation between individual examples - anything.

And I don't believe that any reputable builder, let alone one of the biggest internationally-known builders, would deliberately offload sub-standard product to Canada, the UK or anywhere else. It doesn't make good business sense. I think that rumour is another example of the horseshit-bullshit about quality-builders (not just Martin, I've heard unbelievable tales about Gibson, et al) put around by people who either can't afford or are too tight-arsed to pay for whatever brand they're slagging off.

People talk the same shite about brands of cars which are different to theirs.