Merriam-Webster says:
Definition of prolific
1 : producing young or fruit especially freely : fruitful
2 archaic : causing abundant growth, generation, or reproduction
3 : marked by abundant inventiveness or productivity a prolific composer
I question the writer as he made a mistake. I think the word 'iconic' is what should have been used. #3 above is what he used yet no GT-40 could be called prolific as in they were NOT made in abundance or.....damn it! I'd own one! LOL