Frank:

I have noticed similar small paint cracks, particularly in stripes and roundels, in older models by GMP and Revell Creative Masters that I have bought long after they were originally issued. I am guessing that the paint may shrink slightly over time, opening up these cracks.

I would not polish them. I tried that, and it just made the cracks more noticeable. I have tried paint infills, but that is hard to get just right.

Hope this is helpful,

Don Klema