I painted mine last year and I put a base on before clearing. Most clear coats are formulated to work with a specific base coat and you have a higher risk of clear coat peeling if the base is not used. If you do decide to go clear over gel coat, I would use a high quality brand name clear. For what white base coat cost, I would not risk it but that is just my opinion.
I have painted a lot of cars and the only clears I've had problems with have been budget clears, especially ppg omni line clears. SPI sells a good clear but I think it is too soft.