From the beginning it was clear that this would not be your ordinary Miss America pageant, and each day it becomes a little less ordinary. Today, Bob Guccione is back and the pageant is quivering with anger and trepidation.

Guccione, publisher of Penthouse magazine, said through a spokesman that he has 350 nude color slides of one of the 51 pageant contestants. He won't reveal who the subject is, but said that if she wins on Saturday night, he would print the pictures.

Penthouse spokesman Sy Presten said he expects the subject of the pictures will make it to the top five at least.

"That's how great she is," he said.

"Every time he opens his mouth, he gets a little publicity," pageant chairman Albert A. Marks said later about Guccione. "So what?"

Guccione, Marks said, could be speaking "for his own personal publicity reasons since he has magazines to sell of the usual sleazy variety."

Marks said he had no plans to ask each of the contestants if she is the anonymous model.

"What answer would I get? Fifty-one nos. I won't demean them with the question," he said. "If he is telling the truth, which I doubt, the odds are one in 51 [that Guccione would have photographs of the winner] and I'm not going to upset the entire Miss America pageant because he is seeking publicity."

They're getting a little tired of scandal around here, to say the least. It was Guccione who brought controversy to the pageant this summer when he published explicit nude pictures of the 1984 Miss America, Vanessa Williams. Williams resigned and this year's contestants were, at least until yesterday, finding it hard to persuade reporters to let them talk about anything else.

The next story broke yesterday when reporters discovered that Melissa Bradley, Miss Ohio, was once accused of shoplifting. A flurry of press conferences and interviews and a whole new line of questions followed. But by now, Bradley is old news.

Another day, another scandal.

"I think everyone's pretty desperate for rumors and innuendo and anything that can be the least bit startling," said pageant host Gary Collins. Then, saying what many here must be thinking, he added, "It'll make for some interesting soul-searching tonight."

Contestant Juli Sunday, Miss Oklahoma, said she had one point to make before she launched into the by-now almost obligatory condemnation of Guccione:

"It wasn't me," she said.

"I don't believe it," said Kelly Lin Brumagen, Miss Kentucky. "I think if he really had them he would have published them long before now just to ruin the poor girl, which seems to be his forte."

Said Penthouse's Presten, "Suppose he had said he had pictures of Vanessa Williams several months ago; would anybody have believed him?"