Yes it is possible on the target model at least. Mine came with a rail in the box. It simply attached with screws in the top of the barrel. I think all the targets come with the rail in the box. I had a red dot on mine for a while. It is quite a tight grouper. Edit: mine does not have the tapered barrel, can you see a couple removable set screws in the top of the receiver/barrel?
I'm not sure if it has any screws on it. I do not own the gun yet, but I'm thinking of buying it from a seller on here. I'll have to ask him. Thank you
If people are wondering, there are at least three people in the area who can drill and tap the top of the receiver if it's not already done. In order of increasing price (AFAIK): Greg Derr, Dave Santurri, and LaRocca Gun Works. I'm sure there are others who can do it as well.