Confused if I need to file amended for K-3s

I had invested in some stocks a couple of years back that required K-1's, last year K-3's were not required and I know this year they are.  I have the K-3's but I have seen some conflicting information about whether or not a simple stock investor needs to file an amended return with the K-3's.  Is this required at this point?  

 

Also, one of my investments did not publish a K-3, i'm going to believe that if I dont receive them then thats not on me?

 

Thanks

Jason