I've never had those (I did look at the book briefly - would you mind sharing the recipe?). But based on the dilled tomatoes and the sweet pickled tomatoes I've made, I'd say yes, the green tomatoes do taste quite a bit different from cukes. Not that they're bad, I'd certainly try the recipe if you liked it, but maybe a small batch.

lisa .. I make green tomato pickles almost every year, just as substitution for cucumber. Green tomatoes are actually better and safer when substituted for cucumbers BECAUSE THEY ARE NATURALLY ACIDIC.

Another thing, per my personal experience, they stay crunchy for much longer than cucumbers, without any pickle crisp stuff PROVIDED they are GREEN with no hint of changing color.
I already have some in frig from last year and I have made another jar this year. Just followed dill pickle basic recipe.

Agree that it would change the taste significantly.

Don't know that book at all since no one here uses it that I know of. So posting the recipe would be needed when asking about questions of safety.

Dave