In general they will, yes.  But it'll vary by manufacturer and model.  Older ones will probably have higher resistance than newer ones -- the progress in MOSFET technology in the past ten years has been absolutely astounding.  If you're a circuit designer, you can pretty much select a transistor for your circuit confident in the knowledge that by the time you get a prototype board back for testing, your spiffy new transistor's performance has been superseded by something smaller and with markedly better specifications.