I'm not sure I understand the question. Doo you mean something besides File > Save...?
Officially, no. But there is a trick to do that: you print the booklet to a .ps file and later convert it to .pdf.
Go to Print Booklet, Print Set Up and define the printer as PostScript File. You may need to adjust print configurations accordingly the PPD you use. After that, just Print the booklet. InDesign will ask for name and place to save the .ps file.
In Mac, you can convert this .ps with Preview. Open the .ps file and choose Save As (hold Option key to turn Save into Save As command). Of course, you can also use Acrobat Pro or several other apps which can convert .ps files to .pdf, available on both Mac and Windows.
Besides this, you can export the normal pdf from InDesign and then impose it using another app. In Mac, I like very much PDF Clerk Pro, from Sintraworks, as it is a powerful PDF editor at a reasonable price. In Windows, there is Quite Imposing, a very powerful (although expensive) plug-in to Acrobat Pro. I do not remember the name of stand-alone imposing apps for Windows, but I am sure there were at least two.