In the Late 1970's I had to take a low number Springfield our Police department bought to Roy Dunlap in Tucson for examination.

To summarize what Dunlap told me. Not all low number Springfield's are unsafe. Most are not. Some are unsafe and there is no way to tell which are safe and which are not, so the whole lot was condemned.

In modern phraseology I suppose you could say, "most low number Springfields are not unsafe, some are...guess which one."