Pat, I sold the stuff for one of the 2 remaining domestic manufacturers and ask the same question. There might be a little advantage in testing during manufacturing or installation to find defects but then the specification is hopelessly out-of-date anyway. Compared to the replacement products now on the market, steel pipe--black or galvanized--is a much better choice in my opinion.
If your local building inspectors approved it when it was installed, those are the people that you have to keep happy. I would check with them to determine current code. Pending their approval, I would have no problem at all with it.
One further note is that some home centers have stopped stocking black fittings and nipples. They do stock galvanized. Perhaps the marketplace will ultimately make the decision.
Anybody know what Chicago has done with their spec on lead? The testing cost for compliance at the manufacturer level certainly may get it booted. And from what I have seen of import pipe, I would be more afraid of it than having galvanized in a gas line by far.