My 71 has leaf springs AND coilovers

[JJSimon904]

Hi, I just started my first restoration 1971 GMC 1500 long bed and was surprised at how well it rode right off the bat. Someone changed out the 5 lug rear end with a 6 lug 12bolt. It also has leaf springs with coil overs. I've attached a picture of it. I've done a little research and found that trucks came with one or the other, but not both as far as I can tell. Has anyone come across this before? I eventually want to drop the truck 2/4 but not sure where to begin with a setup like this.




Thanks ahead of time.