It's hard to say, I think, since the only period catalogs we have (1934 and 1940) show pocket watch Type-1 designs only. Others will likely know more from their research. My gut intuition says that converted pocket watches were the first to find their way onto wrists. Here's one I have from 1935, for example:Having looked at lots of information about these I have learnt a lot. However one thing I can't discover is when these movements were first produced as wristwatches . Anybody know ?
But gut intuition is a very poor way to reason your way through Soviet horolgy, so I'll bow out and wait for a true expert to answer.