OK, that motivated me to figure out how to fix this. Changing layers may work, but I don’t know how to do that, so I used brute force instead.
In Fritzing right click on the mega rev3 part and click “edit with new parts editor”, then file->save as new part. From the mine parts bin, export the new part as an fzpz file (right click the part and export part). Unzip the fzpz file and with Inkscape edit the svg.xxxx_pcb.svg file. In xml editor click on “silkscreen” group and shift-cntrl-g multiple time til silkscreen is entirely ungrouped. Edit select all and group. In xml editor step down to the copper1 group and unindent the group (to change it out of the new silkscreen group and back in to root). Set the new group’s id to silkscreen and save the file as plain svg. Rezip the file in to an fzpz file and load it in Fritzing and the silksceen lettering is there. It may be easier to use a text editor and search the file for “text” (I usually use grep in cygwin on windows to do this) to see if there is any hidden text, or edit the svg with a text editor and search for text to see if there is any hidden text to see if the first method is worth trying.
Peter