[plt-scheme] Does SRFI-27 specify repeatable PRNGs?

Hi,

Sorry, I know this is a bit off-topic, but perhaps someone here has  
already stumbled across the answer. I'm looking for a good PRNG that  
is portable, but it needs to be one that allows me to get exactly the  
same PRN sequence from the same seed.

Can I use SRFI-27 for that purpose or does it only specify the  
interface to possibly different PRNGs that might produce different  
sequences?

How about the built-in generator of MzScheme, might it change in  
future or is it part of the specs that it won't change under the hood?

Best,

Erich