I don't know specifics of that as I never used "gear" of any kind. Before DNP at most I used clenbuterol and ECA-related products.
But from what I could gather here and there when I was searching for DNP sources, many of these compounds are produced from legitimate companies but there are "alternatives" brands as well complete forgeries/fakes which is also common in this arena (well the same for pharmaceutical drugs in general).
I don't know specifics about countries but It's safe to assume that if one specific compound is not prohibited in any given place and the same is produced there, it becomes a potential "source".
About clandestine labs, it probably depends on the substance itself and how difficult it's to acquire it.
Well you could go to Amsterdam to experiment all sorts and flavors of pot... the same could be done to other places that have no restrictions for a given drug too.