Yes, thanks all. The simplest response, from ixdude, probably will be what I will do: pinstriping tape over the numbers. And Mustafa, your filing is appropriate if the marks are deep and leave sharp borders. Paul's 'epoxy filler' is probably the best but the most complex.

When you are able to buy an SRT 201 with 1.7/50 Rokkor MD, 2.8/28 Rokkor MD, and JC Penney 80-200, all in near mint condition except for the pervasive engraving, all for USD 30 you simply buy without hesitation. - David Lyga