Not sure the Monitor was available in '34; from potentially faulty memory the 1918A1 did not even come out until '36.
And the Monitor was meant to be a way to shift colt-made BAR in the post '34 sales slump.
But, I could be remembering that wrong.
Bannerman had some spiffy stuff for sale on his island on the Hudson. And was not adverse to selling by the barge-load.
Now, he also was selling field and pack artillery, too. So, getting non-dummy ammo for those 37, 47, or 54mm guns was possible before NFA. Now, how much value that would have today--when it
would need licensing--is debatable. Those Mauser mountain guns do have a pretty devout following in our modern times, but it's a very distinct minority, perhaps a hundred or so owners in the entire US. That lower demand wil lnot give the high prices of other Title II items.
A couple hundred bucks' worth of Standard Oil stock would be worth a lot more, a lot, lot more, today. Minnesota Mining & Manufacturing, E.I. du Pont de Nemours, International Business Machine, all wound up doing pretty good.over that time frame, too.