"The link I provided actually include Emu48CE (the emulation program, the number "48" isn't related to anything) and ROM files of HP38G, HP38G, HP48GX, and HP49G."

Actually it does mean something, the original program was only an emulator for the hp48, but the developer later added support for the 38, 40 and 49 (it also supports the 48G, GX and SX)

The link I provided has just about every version of the emulation program made including a fixed version of the emu for pocket pc, many klm scripts and rom images http://www.hpcalc.org/