As with any movie they obviously used multiple versions. But they were changed for Vol 2 specifically to be easier to handle and wear in the holsters. (Also so they would give a better profile/silhouette, though I can't remember the exact quote.) The angle/bend was done low, just above the under-barrel, which makes it fairly subtle when viewed from certain directions. As mentioned before, marketing prominently features the angled versions:
http://www.therpf.com/attachment.php?attachmentid=725562&d=1493587409
They certainly used flat versions as well, but both got a lot of screen time. However, even the flat versions have had quite a few detail changes to them from those in Vol 1 and they also made them smaller. So there are lots of differences between the Vol 1 and Vol 2 guns either way, for those that care about details. The main differences between the angled and straight Vol 2 versions are the cutouts and angle in the grip.
It's no different than what they did with Han Solo's DL-44, which changed significantly between each film and has had every single detail meticulously discussed and documented.