oldest versions of FF are here (oldest one is 0.8 and there is a tar file with the sources, just in case)
Not sure also how you would get flash card to run efficiently on an old PC (including, from a bandwidth perspective).
32 MB sounds like a PC older than 1998 (I remember my professionnal labptop in june 98 with 32MB standard plus 16 MB ram extension….). Don’t make your breath depend on that….
By the way i think it was running windows95.
You could try to find some old version of Solaris if they still exist, I remember running Netscape on Solaris before then ;)