To clarify: were their gridlines on the 11-foot Enterprise model, 1966-69? Painted or physical? Top and/or bottom?
I am learning new things about her lately (see tallywhacker thread).
Yes, the lines were there, drawn on with pencil.
On my 1/350 scale kit I intend to paint the model with primer then sand and apply another coat of primer before the applying the final hull colour. This should reduce the engraved lines to barely noticeable.