It is certainly a commercial pistol but is identical in every way to the French contract pistols except for the grips. French contract grips were always wood, post-war commercial grips are nearly always not.
Not really sure why you want a spare barrel. Is the original one worn out and smooth? I doubt you will shoot out the barrel other wise. If you really needed a barrel, your best bet is to find another SS made pistol that closely matches yours. It may take a very long time and much patience to find one. When you do, there is a good chance you will have to do minor fitting by hand to get it to work, and then, I would recommend a gunsmith to check it to ensure it is fitting safely. That is why these pistols all have assembly numbers in the first place. Personally, I wouldn't mess with it if my pistol already had a barrel.
Magazines, on the other hand, shouldn't be too hard to find. ANY 9 round Eibar/Ruby style pistol magazine MAY fit, you will never know for sure until you try it in the pistol. Again, some minor hand fitting may be required, but I have many Spanish pistols accept other magazines. You see, the magazine issue was a big problem during WWI and there was no standardization. I'm not saying that after the war there was good standardization, but there were certainly fewer parts suppliers, and fewer manufacturers as a whole. Many manufacturers used sub-contracted parts, such as magazines, so you will find that many of the post-war Spanish pistols with 9 round magazines will interchange because they were made in the same shop. The French Unique, which is really just a very well made Eibar/Ruby style pistol, will feed out of many of the Spanish magazines, and vice versa.
Since your pistol came with generic grips originally, you should also be able to find something close if not an exact match if you just keep looking at EBay, Gunbroker, and other places. It might take some patience, but eventually something will pop up.