I'm glad you asked this question. Are you talking about a table of values for graphing? And one that is completely blank except for the x and y headings? I suppose your transcription would depend on the intended use. In a textbook or a classroom situation, I would omit the table and insert a transcriber's note instructing the reader to create a table of values. When transcribing an exam, as you are doing, I would be more clear about what exactly is on the page. Especially if this is one showing empty fields for inserting data using a computer, which is how many exams are given nowadays.
Empty tables of values don't generally indicate how many values are to be inserted. If it is clear that, say, four x and four y values are to be inserted, then you could use a general omission symbol to indicate each missing value. I think that makes more sense than inserting two guide dots.