Are spider cracks in the gel common ?

[wellcraftv20step]

well i bought my 89 v20 last year, it had a ton of these cracks in it so being the mad mad man that i am i pulled out the dremell and starting, only to find these that every one of them was no deeper than the gelcoat itself. funny i sold my 91 wellcraft 236 coastal and so help me it had not a one, aand i drove it offshore hard for ten years, well mow regelcoating my deck this weekend hope it goes well, only becaus the non skid is worn down