How to verify authenticity of smaller LEGO parts? Can anyone help me identify the logo or mark on some smaller LEGO pieces?


I have many 1*1*2/3 slope with no LEGO stamp but do have a (C) copyright symbol (full circle not just brackets) and a number
Dark green - 3 with no number, n.o 31, n.o 3, n.o 5
Red/brown - n.o 29, 2 with n.o 15.
Trans orange and red - 8 with different or no n.o


The colours are spot on and I can't fault the quality, so I assume these are genuine however I would like to know if this (C) symbol and the general quality is a solid identifying method.

Also with the 1*1 round brick and nose cone - are there ANY markings usually? 

Also with the weapons and tools - I have many with a (C) but some with nothing...

Any hints or tips?
I have many 1*1*2/3 slope


On this piece the LEGO marking should be seen on the flat, semicircular part on the bottom: 


  Dark green - 3 with no number, n.o 31, n.o 3, n.o 5


I'm sorry, but I can't identify this piece, a photo would be helpful here.


  Red/brown - n.o 29, 2 with n.o 15.


Just like here


  Trans orange and red - 8 with different or no n.o


Or here.


  Also with the 1*1 round brick and nose cone - are there ANY markings usually?


Yes, there are, but they are quite tricky to find. On the 1x1 round, you should be able find the marking on the inner side of the top ring, facing down: 

While on the cone, it is similarly on the underside of the flat ring, but close to the bottom, so easier to see: 


  Also with the weapons and tools - I have many with a (C) but some with nothing...


These are quite broad categories, so if you have any specific pieces, I'd love to help you :)