"Thousand Dollars Worth" or "Thousand Dollars' Worth". Is this a Possessive?

These cases aren't tricky if you ask yourself the following question: how would you write "one dollar's worth"?

In other words, "dollar" naturally requires an "s" in this case, even though we are talking about "one dollar".

Therefore, it is a case of possession, meaning that we are referring to the "worth" of "thousands of dollars". So, the possessive apostrophe should fall after the "s".

The same rule applies to "seven years' jail" and "one year's jail". Many journalists etc. are clearly none the wiser about this topic, as even some of the most astute publications contain articles which omit the apostrophe.

The possessive is necessary because you're indicating that the worth or value possessed by the equipment is equivalent to the worth or value possessed by five thousand dollars. Hence, Five thousand dollars' worth

Normally I would say the possessive is necessary, but it is interesting to observe the trend in usage via Google NGrams:

As you can see, the possessive was overwhelmingly preferred beginning in the 1830s, crested around 1920, and after WWII has been in steady decline. It has been putting up roughly the same numbers as "dollars worth" beginning in the late 1970s, and has experienced a slight up-tick since around 2005.

These cases can be very tricky. I've found the following document very helpful in determining when to use apostrophes: Genitive is Not Always Possessive.

The following section (referring to Merriam-Webster’s Dictionary of English Usage) is most relevant to your question:

They discuss a number of uses of the genitive and give examples of each.  Under 'descriptive genitive or classifying genitive', with the comment 'Fries adds the genitive of measure to this', they list:

the room's furnishings
the airplane's speed
the building's foundation
one day's leave
a dollar's worth
a year's wages
the Eighty Years' War