The answer to what you want is to go to a store and hold it in your hands
I use to organize lots of gun club events and the best thing about it was being able to try out things that my friends would show up with. We would even put out requests before hand and ask people to bring a certain firearm out if someone owned it. It was very cool to have some of my requests fulfilled when I got to shoot a 5.45×39 AK next to a 7.62×39 one. I did some long range testing with it and anyone with an honest mind will tell you that it makes sense that the Russians switched over to the 5.45×39 caliber. Shopping for gun accessories online can be a pain and sometimes it’s always best to go back to the manufacturer and ask them.
We’ve had to sell off some of our high end upper receivers whenever we found out that a new version of this was coming out. Sometimes a slight spring or finish occurs on the AR15 complete upper receivers and its all of a sudden an old version. Just look at what Glock did with all of the Generations of Glock firearms and the infamous recalls. I am never one to be the first to buy a firearm because ever since the XD45 came out, I saw guys send them back to the factory for improvements. That never happened to me with my Sig Sauer pistols so it’s sometimes best to know you are venturing into unknown territory if you try something new. Ask questions and try things out or put on your Lewis and Clark.