The 1005 situation was pretty strange. Here's what I think I know about them. In each case the "Prefix" means the first two characters of the serial number. As you can see, only the "Version A" units had the uSD slot available. Memory specified in "GB" is the size of the internal memory of each unit.
Version "A" - NOT Live
Prefix SR = GO 1005 (Australasia = 2050, Germany = 1015???), 4GB + SD
Prefix SQ = GO 1005, (Australasia = 2050 World), 8GB + SD ("World" edition maps)
Version "A" - Live
Prefix SP = GO Live 2050, 4GB + SD
Prefix ST = GO Live 1005 (Australasia = 2050, Germany = 1015???), 8GB + SD
Version "B" - NOT Live
Prefix SE = GO 1005 (U.S. = 2050, Australasia = 1050), 4GB
Prefix SF = GO 1005, 2GB
Prefix SJ = GO 1005 (Australasia = 1050 World, Somewhere = 2050???), 8GB ("World" edition maps)
Version "B" - LIVE
Prefix SA = GO Live 1005 (somewhere =1050 or 2050???), 4GB
Prefix SB = GO Live 1005, 2GB
Prefix SI = GO Live 1005 (Australasia = 1050 World or somewhere = 2050???), 8GB ("World" edition maps)