What type of mint error 0

[Wsn3573]

I have two pennies 1972D and 1964D Lincoln Memorial.  The obverse is relatively clear on each (although 72 wording IGWT is not visible with naked eye but can be seen using microscope) the reverse side of each coin is similar.  The 64 however only shows 6 pilares whereas the 72 shows more building/pilares  what type of error is this and do coins have value .  Sorry for being so long winded, I am just very new to coin collecting and roll hunting  Thanks!,

[B.C]

Both cents are post mint damage but keep looking never know what you might find 

[Wsn3573]

I don't mean to sound disrespectful,  but.....wouldn't these coins be result of a mint weak strike error? I certainly do not have the experience that I'm sure you have but I thought/think the above applies.  Perhaps the pictures that I furnished do not show what no rother strike to reverse is apparent. Thanks again for taking the time to review and replying.

[B.C]

Nah it's ok to ask 

A weak strike would effect both sides of the coin 

Your coin shows scratches I don't know how it happened but I would guess it was stuck and spun in a coin counter