Ok I have found a way to do it. Requires manual edit of the G Code file on a few lines but it works.
I have two separate files - one for the cover and one for the text I want on top in a different color.
My cover is 2mm thick so I edit the G Code with the text to add 2mm to the Z parameter in the G90 command following each LAYER comment. in my case I have 5 layers of text so I had to change 5 lines of G Code. I load the G Code into WORD and use the "CTRL-F" to search for "LAYER:" to find the lines to edit... usually 2 below the layer comment is the G90 with x,y,and z absolute values. change the z values to raise the head over the top of the cover. this took about 3 minutes the first time to do it and save the new G Code file to the SD card for printing.
My original Z values were 0.2, 0.4. 0.6. 0.8, and 1.0... they become 2.2, 2.4, 2.6, 2.8, and 3.0.
So I print the cover in color #1 and then load the text G Code that I edited, change the filament and print the second file in the second color.
Do NOT remove the cover from the build plate or you will never get it realigned and it will slip during printing.
Be sure the saved file is ".gcode" and not ".txt" becuase the printer will not recognize the ".txt"
Also this is with "Marlin" flavor of G Code....
Tested this last night - it works.
Cheers,
Rob