Is the barrel drilled and tapped for a front target scope block?
Yes, I think. There are two drilled-and-tapped holes in the barrel. They're roughly 2 inches apart aligned front to back on the barrel.
Does it have a clip slot?
I'm not sure. On the top of the receiver at the back of the loading/ejection port, there's a roughly oval cutout. Is that the clip slot?
I'll get photos of both.