Did the Witch of Endor really bring up Samuel?

I think there can be no doubt that it was Samuel that appeared to Saul in 1 Sam 28:7-19 and not a demon imitating Samuel. From the description in the passage, it seems that the Witch of Endor was used to seeing demons in disguise when she conjured up departed spirits.

However, on this occasion, she seems to have been shocked and unprepared for what she saw:

When the woman saw Samuel, she cried out with a loud voice; and the woman spoke to Saul, saying, “Why have you deceived me? For you are Saul.” 1 Sam 28:12

She seems to have recognized that this really was Samuel and somehow also at the same time realized that the man in disguise was King Saul--probably from taking a closer look at him based on her surprise at actually having brought up Samuel.

I would say that the Lord simply allowed Samuel to come from Paradise and appear to Saul and pronounce the judgement on Saul in verses 15-19. It seems possible that the departed righteous dead can appear to the living based on these passages:

Luke 16:27-31 Lazarus and the Rich Man:
27“And he said, ‘Then I beg you, father, that you send him (Lazarus) to my father’s house— 28for I have five brothers—in order that he may warn them, so that they will not also come to this place of torment.’ 29“But Abraham said, ‘They have Moses and the Prophets; let them hear them.’ 30“But he said, ‘No, father Abraham, but if someone goes to them from the dead, they will repent!’ 31“But he said to him, ‘If they do not listen to Moses and the Prophets, they will not be persuaded even if someone rises from the dead.’”

2 Kings 13:21 Elisha's Tomb:
Once while some Israelites were burying a man, suddenly they saw a band of raiders; so they threw the man's body into Elisha's tomb. When the body touched Elisha's bones, the man came to life and stood up on his feet.

Matt 27:52-53 - At Jesus' Resurrection:
52The tombs were opened, and many bodies of the saints who had fallen asleep were raised; 53and coming out of the tombs after His resurrection they entered the holy city and appeared to many.