Quick way to check front sight cant:
First, center your rear sight, then take a piece of string or rubber band (I prefer rubber band) and run it tight through the rear peep sight to the front post.
Now look straight down the length of the rifle, it should be centered all the way.
If it veers to one side then you have canted sights.

Since the gas block/front sights are pinned the only remedies are to send it back or replace the gas block with one the uses set screws to hold it in place (so you can center it).

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