If it is not then there is a strong chance that the version the bureau will use to print the job may change the flow and layout of the fonts in the print. Sometimes this will not matter, other times this is critical and will not print as expected. If you are worried about legal issues with supplying fonts then convert all the text to curves before sending the document to the bureau. Anybody who supplies fonts to a bureau is not actually breaking the law - it is the bureau which uses them to print the job that is breaking the law. Most law abiding bureau's will phone the appropriate font manufacturer and will ask for a licence for using the fonts in question.
Postscript fonts have two parts.
A screen font and a printer font - both are required to successfully print the job. Failure to supply either the screen fonts or printer fonts will mean that the job cannot be printed until they are supplied. Fontographer can convert Truetype fonts to Postscript. This is particularly useful if the job has been created in Quark - all you would have to do is convert the font to Postscript and substitute the font when opening the Quark document. Fontographer will also convert between PC Truetype fonts and Macintosh Postscript fonts.