1962 Penny. Grading Exercise. Opinions Please Gang.

Yes,the coin is UNC but has a little bit of RUB from being in a loosely rolled roll,the coins either side have rubbed it a little.

Au
could be cleaned, Hard to tell without the coin in hand
With the typical weak strike on the obverse

Now just to make it a bit trickier then. Where would it fit in these sub gradings. I'm thinking AU-55?
AU-50
This is for "About Uncirculated" (the grade) and "50" (the numerical designation of that grade). Also called "Almost Uncirculated-50." This is the lowest of the four AU grades, with the others being AU53, AU55, and AU58. Between 50% and 100% of the surfaces will exhibit luster disturbances, and perhaps the only luster still in evidence will be in the protected areas. The high points of the coin will have wear that is easily visible to the naked eye.
Look at examples of AU-50 coins on ebay
AU-53
This is for "About Uncirculated" (the grade) and "53" (the numerical designation of that grade). Also called "Almost Uncirculated-53." There is obvious wear on the high points with light friction covering 50-75% of the fields. There are noticeable luster breaks, with most of the luster still intact in the protected areas.
Look at examples of AU-53 coins on ebay
AU-55
This is for "About Uncirculated" (the grade) and "55" (the numerical designation of that grade). Also called "Almost Uncirculated-55." There is slight wear on the high points with minor friction in the fields. Luster can range from almost nonexistent to virtually full, but it will be missing from the high points. The grade of "Choice AU" equates to AU55.
Look at examples of AU-55 coins on ebay
AU-58
This is for "About Uncirculated" (the grade) and "58" (the numerical designation of that grade). Also called "Almost Uncirculated-58." There is the slightest wear on the high points, even though it may be necessary to tilt the coin towards the light source to see the friction. In many cases the reverse of an AU58 coin will be fully Mint State. Less than 10% of the surface area will show luster breaks. The grade of "Borderline Unc" equates to AU58.
Look at examples of AU-58 coins on ebay

You aint wrong enwarb
Good call

All this number stuff is American and it is widely accepted they are lenient when grading. Sap has mentioned in several posts that TPG companies dont used magnification when they grade and I think this goes to show unless your eyes absolutely need it its better to grade it with the naked eye.

Ok, now this seems a bit confusing.
Firstly, is there a published standard for grades/grading. If so, where do I find it please?
Second, Are we saying that forensic examination, ie. to check for fakes is ok but grading should be done with the naked eye?

Lostnfound I'm sorry for confusing you but coin grading is a bit of an art form. After a while you get a sense for a coin photographic or in hand is the best.
I an no way an expert in the field of grading but I do know the basics and I am hard on my own coins.
Until you get a BU or proof coin in hand then grade backwards from that for the same coin and grade it accordingly you can't understand.
A lot of pple grade from the bottom up eg, aGood to BU, I tend to grade from the top down.
It works for me