Out of curiosity, would you still recommend the L3+? As I've got my 3 out of retirement to run a bit more and expect to re-retire them by November when the L7+'s will hit the market (or October when Bitmain is "testing" them). But that's with 15-20 cents EUR electric pricing, for most of the year. If the difficulty will triple (which is the lowest of my expectations) unless LTC goes 3 times up, I don't see them running much longer.
To be honest, I doubt that the cost of Litecoin will triple, otherwise the capitalization of the entire market should be 5 or 6 trilons, which seems to me a colossal figure. So I suppose L3 + will become obsolete by this time ... especially considering the very high cost of electricity. By the way, when you talked about Bitman, what did you mean? It's just that I have heard more than once from different people the myth that before the delivery of equipment, Bitman uses new equipment for some time, in fact, sending the used goods.
Well, LTC has been double today's price before, but yeah, triple would be a stretch.
Regarding Bitmain, I've seen from several people that they got machines that had dust on the fans when taken out of the box. Haven't had this myself, but I'm not a hardware buyer. Plus there have been reports on spikes in difficulty up to a month before shipping was scheduled for the first batch. No hard evidence, at least not of recent date.
From a QC perspective, you'd want each machine to run at least a day to verify nothing is the matter, the question is how long they "take" this "day" for testing. I could argue 7 days is a reasonable testing period too for quality control with mining machines like these.
Then, from a business perspective, it would be insane not to have machines you promised to deliver 3 weeks from that day run as part of the "quality control" when they're basically printing money at a 4 times higher rate than any other machine on the market.
So summarizing, I'd be surprised if they didn't do any runs before shipment.