Check that coin again. No coins that year contain a mint mark, nor did the P mint mark appear on dimes until 1980.
If the coin is the same thickness as a regular dime it's been plated and is only worth face value. If it's thinner than a regular dime and is copper on one side only, the cupronickel cladding un-bonded from the core. This is called a lamination error and is worth around $5 or $6 Note there's no such thing as a 1967-P dime because US coins dated 1965, 1966, and 1967 don't carry mint marks.
A 1975 no mint mark dime weighs 2.5 grams. This weight is standard for dimes produced in the United States since 1965, which are composed of 75% copper and 25% nickel.
No "W" mint mark on a 1923 Dime, it's the designers monogram (A. Weinman) the mint mark is on the reverse to the left of the fasces
10 cents. It is struck in copper-nickel and unless it is a proof coin or in a special mint set, it has no collector premium just like any other dime struck after 1964.
what is the value for a 1972 dime
With no D mint mark or no mint mark at all it's from Philadelphia.
It's just a dime, spend it.
No mint mark indicates that the dime was minted in Philadelphia.
On the reverse of the coin under the wreath. It's a S or O mint mark, but without a mint mark it was struck in Philadelphia.
That's "backWARDS", not "words", and 1967 dimes didn't have mint marks. Mint marks were not used on any U.S. coins from 1965 to 1967. Please post a new question indicating where the backwards letter or number is located with respect to the rest of the design.
The mint mark is located on the reverse [tails] side of the coin at the bottom below the wreath. If there is no mint mark then the coin was minted at the Philadelphia Mint.
The coin is only face value. No U.S. coin dated 1965,1966 or 1967 will have a mintmark.