Yes, the law set the value of the Shekel, and the price of certain things (like the redemption of the firstborn...), virtually preventing any possibility of inflation. (The price remained unchanged for millenia)
The idea remained when the currency was tied to commodities (i.e. gold & silver), but the dollar has long since been freed from its bondage to gold.
I was stumped by the fall in the price of gold in particular, as usually the dollar's decline is accompanied by the rise in gold. I finally heard the explanation a couple of weeks ago (or more now). It has to do with the hedge funds needing to liquidate, and being heavily leveraged in gold having invested in gold when it looked like there was no end to its ascent. Now their need for money to pay back the debt they had required them to sell the gold. This flooded the market and the law of supply and demand took over.
Gold remains very popular, just there was a glut of it in the market. That sudden influx of gold is tapering off, and we should see gold resume its upward trend.
A lot of the commodities value has been affected by a general fear of the future, and the industrial demand falling. Gold, Silver, copper, et al. have more than just a trade value, but have a large industrial value besides, being used in manufacturing etc. As the manufacturing sector declines, that particular demand falls as well. Platinum was affected by this trend in particular (as I understand).
Precious metal are, have been, and very likely will remain a safe haven. They are never worth zero, and have inherent value (e.g. industrial use) that federal reserve notes can never claim.