Of course, you could replace the whole gas block with a more traditional, barrel-mounted A-Frame, if you like. Or, you could use one of the
collapsible A-Frames and have the best of both worlds...
It's funny - Mine is a Double Star flat-top, and my wife's recently purchased gun is a S&W M&P15OR. I had actually noticed the height difference in the front block for the first time about two weeks ago.
It appears that you have a couple of choices, though. Get the front sight intended for hand guard mounting, or replace the front block - which really isn't all that big a deal in my experience. I would certainly do some homework before diving into any such operation - or let a pro do it. When I
replaced my front block, I was honestly pretty nervous about it. In the end, it was really easy though. That being said, I don't think that all of these things secure to the barrel in the same way. I could be mistaken, as I don't know the guns really well yet.