Early returns are suggesting a potentially regal post-Oscars boost for Weinstein Co.’s “The King’s Speech,” with solid mid-week figures comparable to past pic winners like “Slumdog Millionaire” and “Chicago.”

But as “The King’s Speech” enters its first post-Oscar weekend (its 15th frame) with a cume of $115.8 million, some bizzers question whether how much of an impact its revised PG-13 rating will have on the film’s future take.

Fox Searchlight’s R-rated 2008 pic winner “Slumdog Millionaire,” which grossed $1.2 million the day following the Oscarcast (Feb. 23, 2009), was in its 15th week of release, while Miramax’s PG-13-rated “Chicago” — in its 13th week in 2003 — tallied $856,805 the day after winning best pic. By comparison, “The King’s Speech” grossed on Monday $731,453, but saw an increase the next day with $872,002.

“Slumdog” grossed an overall $141.3 million, of which $53.6 million came between nominations and awards; “Chicago” earned $69.1 million during that same time frame, before cuming $170.7 million domestically.

If mid-week perfs continue to hold, along with favorable weekends, “The King’s Speech” should wind up with another $40 million domestically, according to B.O. pundits, which would be comparable to post-Oscar bumps for “Slumdog” ($42.9 million) and “Chicago” ($36.7 million).

The pic’s less-restrictive rating could lead to wider aud turnout, but bizzers aren’t sure how many moviegoers under 17 will purchase ducats to the historical drama.

In order to secure the PG-13 rating, TWC eliminated the sound from the offending f-bombs, the source of TWC’s original ratings appeal last year. TWC intended the new rating to allow schools and other organizations more freedom in purchasing tickets.

TWC hasn’t yet firmed a launch date for the newly-rated version, though it won’t have to wait for the typical 90-day withdrawal period normally mandated by the Motion Picture Assn. of America.

“We thank the MPAA for their speedy and sensitive consideration of the alternative version of ‘The King’s Speech,'” TWC’s COO David Glasser said in a statement last Friday. “At this time, TWC and the filmmakers are discussing the appropriate next steps.”

Those steps will have to involve the cost of replacing prints, either film or digital, and the rate at which they can be implemented in theaters. Currently, “The King’s Speech” is playing at 2,385 runs, less than “Chicago” during the same time in 2003, but more than “Slumdog.”

Whether “The King’s Speech” lives up to previous post-Oscars benchmark set by “Chicago” or “Slumdog,” the Weinstein pic unquestionably has made its mark at plexes nationwide. The extent of that mark hinges on how much its demo base will broaden.