Most of your older games utilizing sampled sounds (not so old as to be simple beeps and buzzes and not using things like CDs for audio) are sampled at 8kHz, maybe 16-22.01 if you're lucky. Mr. Nyquist says that you have to sample at 2x the highest frequency component of your input band-limited signal. So 8kHz samples get you a maximum of 4kHz out, 16 gives 8, 22 gives 11, etc. There's usually also a high pass filter around 100-250Hz to get rid of 60Hz hum from power lines. In other words, figure 100Hz to perhaps 8kHz.
The theme song on TMNT is sampled at 20kHz, and it's often considered something of an oddity - there's an entire ROM on that board dedicated to holding the theme song that players considered so dear. The samples used for SFX and to create the music on Daytona are mostly sampled at 8kHz, some down at 4kHz. This seems a bit more normal.
Note that modern arcade games use much more sophisticated sound systems often capable of CD quality audio (heck, some of them are nothing more than red book CD audio). CD audio is sampled at 44.1kHz.