I might be wrong , but I think the GBU39 supports GPS targeting. But when I equip the GBU38 it doesn't come up with an option for GPS targeting. Also, is there a way to get the GBU39 when using external weapons?
Looking in the config viewer:
Tan - A3_GPNVG18_F
Black - A3_GPNVG18_BLK_F
Tan with battery - A3_GPNVG18b_F
Black with battery - A3_GPNVG18b_BLK_F
Edit
Just updated and noticed that there is now also Recon models:
Tan Recon - A3_GPNVG18_REC_F
Black Recon - A3_GPNVG18_REC_BLK_F
Tan with battery Recon - A3_GPNVG18b_REC_F
Black with battery Recon - A3_GPNVG18b_REC_BLK_F