1958 D Penny RPM Error? Date Looks Stacked Also?

I can clearly see a 1 and a 9 and a 5 twice

Well if it is incuse this could be Machine Doubling. Especially of you see it on the date and the mintmark:



If it looks like this, then it was damaged by the machine after the strike. Not a doubled die. Just device alteration after the strike. These are common.

If the affected area is on the same size as the other Machine Doubling, it is all caused after the strike. Note on the 1970-S image I posted. Note the MD on the date and the mintmark is in the same direction on that coin? Maybe a closer view of the mintmark would he me see what your seeing. (But not necessary if it is in the same direction as the affected date area)

Just rechecked your first images. I think I see what your are seeing now. On the tail of the '9' and the NW corner of the mintmark, that area took a hit on that area. PSD (Post Strike Damage)

If it is Elmers glue it will come off. Other glues may not.

Acetone. That was the chemical often used on coins to take off glue. My brain was doing a search for that word, but when you mentioned nail polish, then it came to me. (I was actually thinking nail polish before and still couldn't come up with that word either then)

Still a hole filler for an album coin.

I'd have a hard time spending up to $50+ to have a coin worth less than a dollar or two to be graded and never get the grading fees back when you sell the coin? I wouldn't do it. I pay nothing extra for a graded coin.
If it were a high grade coin it might be worth it:
https://www.PCGS.com/cert/39491822
https://www.PCGS.com/cert/38783771
https://www.PCGS.com/cert/30423812
https://www.PCGS.com/cert/39265735
Check out the value they give for these grades of coins. Look at each one and see if your coin would be worth the grading fees? The value drops fast on these.

I would not both having it graded/appraised. Not worth the effect to tell you the truth.

Did I read it correctly that you used WD-40 on this coin? Please don't do that... any sort of cleaning destroys value. Any sort.

to the CCF! Please read through past postings and I'm sure you'll learn a lot.

For future reference, sharp close ups of areas in question helps us to help you.