The SideSaddle is for a Benelli 90. It fits fine.
There is a slight scallop above the triggerguard on the Beretta, whereas the Benelli is a straight line. No problems fitting, though. Beretta owns Benelli, so they're 'identical cousins'.
The shroud was installed by a 'gunsmith' who is no longer in business. He used a dovetail blank and screwed it down into the rear sight base. The front of the shroud was shimmed with ???, coulda been pop can material wrapped in masking tape; not sure.
The stock is made by Choate, as far as I know, but, it has the Beretta logo on it. That's the only difference I can tell. If your gun is pre-ban, the Choate will fit perfectly.
No problem if your 1201FP was made prior to Sept. 13, 1994, the official 'pre-ban' date.
My 1201 has the letter code 'BC', indicating 1993 mfg. It came that way. Official designation: 1201FPG3.
Letter code dates according to the Modern Beretta Firearms book by Gene Gangarosa Jr. :
AP='86
AS='87
AT='88
AU='89
AZ='90
BA='91
BB='92
BC='93
BD='94
These date codes apply to the pistols, too.
Check the gun for mfg. date so you don't inadvertantly assemble an "assault weapon".
I had an unfired post-ban version I traded for a Beretta pistol. I wanted the pistolgrip version and got it when I had my FFL.
Shoulda kept it and had 2!
Oh, well.
The accessories are all listed in the Brownells catalog.
If your 1201 is post-ban, you might be able to get a different buttstock that has extra shell carrying capability. Speedfeed, Choate, Advanced Technologies, Butler Creek may have something to allow for a more satisfying 'tactical' look to it.
Good luck, and have fun shopping.