Yixing Teapot ...Help!

I have a (very) little experience with Yixing teapots. I picked up this one because it has a lot of extra markings along with the square 'cartouche' that I usually see. It is pretty plain but does look as it has had some use. I haven't cleaned it up at all. I have no idea if this is a teapot that was made 'yesterday' or if it might be older? Are the extra markings superfluous or could they possibly identify the maker? All thoughts welcome... Thanks for looking and any input you may have!

 

I'm certainly no expert but I was once told to look at the inside of the pot for signs of use. An old pot would have been used and the interior would be darkly stained from tea. I'm sure there are some exceptions as there always are.

 

No dark stains as from tea. But obviously used...probably a young teapot. Thanks for your input!

 

from the base i have certainity this one is not old,but i can't help with the mark,probably 2nd half of 20th century?