92 trooper speaker question
 

Hi,
I'm new to this forum as well as Isuzu ownership. I just bought a 92 Trooper S because some jerk pulled out in front of me and caused my Suzuki to be totaled. The price was right on the Trooper, and it runs nice, so I snatched it up. I noticed that both front doors each contain a speaker for the radio. Also, there seems to be a place for a speaker to the right of the glovebox on the dash, but nowhere on the drivers side. Why would there be space for 2 speakers on the passenger side but only 1 on the drivers side?