1977 -- 3 over 7 -- penny ?

[Akin]

In the midst of my coin scavenging, an oddity caught my eye on this 1977, no mint mark penny. Along with the numerous die breaks/gouges, the most noticeable discrepancy is what appears to be a "3," punched over the one's place "7," in the date; upon further examination I noticed the "ghosted," imprint of a 7 directly to the left of the "1," in the date and above, along with a possible "P," imprint, a "D," imprint, an obscure "T," imprint and an "S," located next to the "T,". Both the "P," and "D," are located near the lower breast region on Lincoln, the "T," is located on the reverse side,by the "E," in "E Pluribus,". The obscure "S," imprint is located by "E," from the previous sentence. My knowledge is relatively limited in regard to this unorthodox error and am curious if anyone can verify or debunk my assumptions with this coin.

[Akin]

[Akin]

[Akin]

[Akin]

[Akin]

[Just Bob]

First, you must ask yourself what could have caused a mint worker to punch a "3" over a "7". I can't think of a single reason for that to happen, so that explanation is unlikely. The most likely explanation is that whatever caused the damage to the first "7" is what also what created the odd looking second "7". The fact that it resembles a numeral "3" is coincidental.

What you see next to the "1" might be strike doubling, possibly caused by a deteriorating die,although it, too, could also be just damage.

As for the other "letters" that you found in various places, those appear to be caused by damage to a coin stuck by worn dies. They, like the above example,  resemble letters by coincidence, although in some cases, they might have actually been caused by contact with a letter on the face of another coin, causing the damage on your coin to resemble that letter.

[Mohawk]

I agree with Bob's assessment.  Definitely a combination of some die deterioration doubling, post minting damage and corrosion creating what you are seeing on that coin.