I think it must in fact be a 620, not 630. Shucks, but it was destined to be beater/grocery-getter anyway, so I'm not too disappointed.
In the meantime, I found an old review from 1973 Popular Mechanics, which I quote:
Jeunet Model 620 ($160): A good 10-speed bicycle, in rather limited distribution yet. It has a high-carbon steel, lugged frame, with chromed fork and stay tips. Its three-pin steel dual chainwheel with 46 and 52 teeth, with the 14 to 26-tooth rear freewheel gear cluster, makes this a rather narrow-range model that’s fine for teenagers but not geared high enough for most people over 30. Ribs and hubs are aluminum alloy with tubular tires and quick release. Lyotard steel pedals have toe clips and straps. The saddle is molded vinyl, which is rather hard for most people. Handlebars and stem are aluminum alloy. Frame sizes are 21, 23, and 25 inches. The 620 comes with Simplex Prestige derailleurs and a pump mounted in brazed-on pump clips on the top tube. This is a handsome machine that weighs only 25 pounds. There’s a lot of handwork in its stripping and finishing.
The article [
CLICK], "Best Bikes to Buy: Chosen and Rated by Eugene Sloane" is the feature article from the June 1973 issue of
Popular Mechanics. It may be of interest to others, as it serves as a buyer's guide of best bikes in different price ranges, including the Peugeot PX-10 and Schwinn Paramount (P15-9)--bikes which have certainly stood the test of time.