Magnum_force,
I looked at the web site and saw T2 is listed there but
I will still have to disagree about the SPAS being used in that specific scene. I have no doubt one was used in the movie but for that specific scene, I know it was a folding stock 870. And I can tell you why. If you have never handled or fired a SPAS it is a very bulky/heavy shotgun with a very large forend that has a pumping mechanism that takes some effort to pump.
In the scene Linda Hamilton does the "one handed pump" thing to work the action. Not only would it be very hard to hold onto the forend one handed and support the weight of the weapon, it would take a tremendoud amount of effort to use the inertial weight of the shotgun to cycle the action one handed.
As far a my 870 in the pic. It started life as an 870 express which is the no frills version of the regular 870 wingmaster. I cut the barrel off at 18.5" and re-installed the bead sight. The forearm is compact rubber grip made by Pachmayer. The folding stock is a factory Remington folding stock which I affectionally call the "humpback." These come on their 870 police SG's and they come up for sale now and then. I have also added a Choat +2 magazine extension and a sidesaddle shell carrier to it.
Except for the sidesaddle you could get the very same thing by buying a Remington folding stock version of thier 870 Police. It already has the stock, short barrel and mag extension.