[Kenwood] Firmware update TS 480

[Joe]

I have a Kenwood 480SAT SNO 80500057 The checksum is USBM 4F70. I got that by holding the NR and mic buttons while powerinb on the rig. With this information, can anyone tell me what firmware I have and if I would notice anything different especially in the audio? I'm totally blind but could get help with the update. I could do it myself, but I'm not sure where the switch is that one must flip that's inside the rig.
 Also I'd like to know where I could get replacement serews fore the top cover since a few of them have gnarled heads. Thanks and 73. Joe.