Unless they are in Brilliant Uncirculated or Proof condition, probably not.
Remember, there were no mintmarks used at all in 1965 through 1967, and dimes minted at Philadelphia before 1980 do not have mint marks* so the lack of a "P" simply means your 1978 coin came from Philadelphia.
(*) the usual term is "mark" rather than "stamp"
It depends on when it was minted. Anything 1971-present is only worth face value. Kennedy halves from 1965-70 are worth around $5, and anything 1964 or earlier is worth at least $12.
Yes.
In perfect condition - 25 cents.
The value really depends on the date, so without more details it's impossible to give a specific answer. Anything before 1965 is worth at least $12 for the silver content; halves 1965-70 are worth about $5 each, and those 1971-present are worth face value.
Yes. About five cents if I'm not mistaken.
They're worth about $2.50 a piece for the silver.
Scott 1271 was a commemorative a Spanish Explorer. This 5 cent stamp was issued in 1965. It can be purchased in mint condition for 50 cents and used for minimal value.
Minimal Value a few cents at most.
Those minted from 1946-64 are worth around $2.50, and anything 1965-present is worth face value.
October 20 1965 - 5d Xmas stamp. Norm
Found an old agway stock Certificate in my late Aunts belongings is it worth persuing to see if it is worth anything? it is from 1965
Those minted before 1965 are 90% silver and currently worth just under $5. Anything 1965-present is copper/nickel and worth face value only.