If you have the chance I'd go shoot the 391 again before buying it and write down which model and specs it is. The Sporting model says "Sporting" along the top of the barrel.
What length barrel did you shoot? 28"? 30"? Other?
In terms of recoil, all of the 391's should be the same (not the Extrema 3.5" though). Once you have selected a gun, which load you shoot will be the next factor in recoil. I have an AL391 Sporting model with 30" barrel and I've tried several loads for shooting clay targets. I started out shooting Winchester AA Super Sporting target loads and they were taking my shoulder off. My local shooting place has Fiocchi as their standard shell for sale and those are ok for me. I tried a case of Winchester AA Light Target Loads and I really liked those. I intend to buy more of those for shooting skeet and maybe trap. I'm not sure I'd use them for sporting clays.
Assuming you are in the U.S.A., the Beretta website that you want to look at is:
http://www.berettausa.com
When you look at the list of products, they separate them into two broad categories: Field guns, and Competition guns. There are AL391's in both categories, but the ones that we've been talking about are in the Competitions guns section.
Good luck on your purchase. Don't rush into it. Make sure you get what you want or wait until you know what it is you really want.