How is the year for a 5 mm blue streak pellet rifle sn 07916 found?

It was made in 1975. (Today Crosman owns Sheridan.) See the link below and then scroll down to "Sheridan"

I must know the Condition of the rifle to give a more accurate value. But the values fall between $50 in poor condition to $235 in like new condition. Without a scratch on it and no wear.

It was made sometime between 1965 -1974

Here is the link to all of the manuals for Sheridan and Benjamin. Crosman owns Sheridan and BenjaminSee the link below.

1825 days