NEW YORK — “Young Frankenstein” played seven previews last week, and, although producers have bucked Broadway tradition by declining to report sales figures, estimates put “Frankenstein” B.O. somewhere in the area of $1.5 million.Of course, there’s also talk going around town of plenty of empty seats at the Hilton, where “Frankenstein” started previews Oct. 11. Such chatter speculates that second-party vendors snapped up tickets at the box office but are having trouble offloading them. In any event, it was a relatively strong week for the Rialto overall, with total sales up about $1.8 million (incorporating the “Frankenstein” estimates). “Wicked” ($1,449,978) still topped the chart of confirmed numbers, while “Jersey Boys” ($1,284,622) broke the house record at the August Wilson yet again. “Curtains” ($819,101) gained almost $270,000 of B.O. traction with star David Hyde Pierce back from a week’s vacation, while “The Color Purple” got a $115,000 bump. Among the rapidly expanding ranks of Broadway plays, the revival of “Cyrano de Bergerac” ($667,608), starring Kevin Kline and Jennifer Garner, powered along nicely in its first full week of previews, with houses about 85% full. The latest from Tom Stoppard, “Rock ‘n’ Roll” ($138,107), attracted crowds in its first two previews, bringing in auds at more than 92% of capacity. Aaron Sorkin’s new play “The Farnsworth Invention” ($190,545) started more slowly in its initial seven-preview week. Over at the Roundabout’s Rialto houses, “Pygmalion” ($228,601) took a slide, unsurprising for a show’s opening week, and “The Ritz” ($301,058), which recently extended, was up more than $50,000. Otherwise, the box office ups and downs were relatively modest, with few shows changing more than $25,000 in either direction. The 22 musicals grossed $15,395,270 ($16,895,270 estimated) for 88.6% of the Broadway total, with an attendance of 192,099 at 86.9% capacity and average paid admission of $80.14. The seven plays grossed $1,986,840 for 11.4% of the Broadway total, with an attendance of 33,912 at 75.7% capacity and average paid admission of $58.59. Average paid admission was $76.93 for all shows.