The Revell (ex-Monogram) 1/72 B-26 is pretty crude and inaccurate, so from the scale accuracy point of view, it really doesn't matter that much one way or the other. Generally, though, B-26s were nice and smooth, so rivets should be sanded down.
If you want a decent 1/72 B-26, go for the Airfix one. The Hasegawa kit is better in some respects, but it's twice the price and nowhere near twice as good.
Cheers,
Chris.
Cute and cuddly, boys, cute and cuddly!