The question was: "Can I save a backup copy at the same time as I save 
the file?"

That seemed like a very good idea for a script. 

GetPubName >> myPubName
a = LenLen(myPubName)
b = a-6
myFileStub = SubStr(myPubName,1,b)
myBackUp = myFileStub + "1" + ".p65"
SaveAs myBackUp,publication,none
SaveAs myPubName,publication,none

This assumes you are using ".p65" as the extension (the script 
would be simpler for Mac users who don't want to use extensions).

It finds the file name, knocks off the extension, adds a figure 1, 
puts the extension back and saves it. Then it saves back to the 
original file name.

The problem with this is that if you use it too often you may 
overwrite a good backup with a bad one before you know it.

An improvement would be to include something based on the time 
in the file name. This could be done with the GetTime script query. 
For example, the following would add the number of ticks since you 
started the computer to the file name (this works for Mac, and for 
WinNT, but may not work in older Win95 etc where it may just give 
a zero)

GetPubName >> myPubName
a = LenLen(myPubName)
b = a-6
myFileStub = SubStr(myPubName,1,b)
GetTime >> ...,...,...,...,...,...,...,myTick
myBackUp = myFileStub + ""(myTick) + ".p65"
SaveAs myBackUp,publication,none
SaveAs myPubName,publication,none

This could quickly create a swag of files on your drive, so you 
would need to do some regular housekeeping.