I believe Vic86 means a thumbless grip (false grip) vs a overhand grip (regular). And referring to a pulling motion. For an overhead pull (chin/lat machine/etc) some find the thumbless grip better because it seems to affect the lat's more themselves, rather than the influence of the biceps. Usually an extra wide to medium hand spacing with a false grip. Seems also to hit the rear delts better. Gironda featured this version quite a bit. Considered it a better way to have the mind focus more on the lat's, not just the pull.
Bentover rows (and even upright rows) have been used with a false grip. But with the angle of the pull, most guy's prefer the regular thumb over the bar style. To some it gives more confidence to the lift when using heavier weight. One of the better lat builders (according to many BB'ers I have talked to) is the medium to close grip underhand curl grip. using the regular thumbs over the bar grip.
Guess it's all question of what works the best for you, thumb or thumbless.Might want to give a good trial run on both to see what suits the personal needs. Might add that doing Dl's with a thumbless grip can go a far way to develop a much improved grip. As can chins, with extra weight strapped on.
Also thumbless push press bench's and overhead pressing can allow more weight to be used on the bar. Though having the bar rest on the heels of the hand may need extra caution. Good spotters should be near by. Not recommended for everyone. Good Luck.