Proof Like Sets.

And you have to be very careful about the packaging of the earlier PL sets. Many circulation sets were put into similar cardboard holders so the state of the coins can't be determined solely on the packaging. The Charlton catalog has a good write-up of what the genuine holders looked like (most often stamped with the Mint's name and address on Sussex Drive).

I'm guessing these would be original PL sets?

Guessing is right. It has the appearance of the original RCM packaging. The original cellophane quickly became brittle,fragile, and somewhat opaque.Seems that on most sets the original plastic was repaired or replaced,sometimes one or more coins was replaced with a circulation strike. Many sets with with tears by the dollar like yours had the dollar removed and replaced with a circulation coin.As well these cardboard holders were widely available and many sets in them are simply after market assembled sets. The only way to tell if the set is original is to examine all the coins to ensure they are all PL strikes. About twenty years ago I learned a very expensive lesson while buying the '53-'60 sets from unreputable or unknowledgeable dealers.Be careful!

Isn't it also true that even if it is a completely genuine early set of coins from the mint, 0-6 could be PL?

If an original proof set was found in a holder that was in less than perfect condition, would it be better to replace the holder? If the holder was replaced would it lower the set value?

Yes, changing the holder would reduce the value. It would be like cleaning a coin to make it look better. It is the original holder that drives up the prices. Compare value of pre 61 sets in cardboard to the later issues in pliofilm. Also, to change cardboard, what would become of the the original cellophane jacket which most collectors would require.

Any information on this set, I've not seen another like it.

I had the RT right then, thanks, that did help.