As is the case with most low priced sporting goods, there is little information available on the web for the Compac brand or this particular model.
A number of different spinning and and spincast reels were sold under the Compac brand from the 1950's to the 70's, all inexpensive and all were made in Japan.
As for this particular model, my best guess is that it was produced in the late fifties and into the early 1960's but I am not aware of any websites or other sources of data, which list the production years for Compac reels. Querying the scanned newspapers on Google News, I did find an ad for Stambaugh-Thompson's Department Store that had been printed in the March 17, 1963 edition of the Youngstown Vindicator, which listed the Compac Sierra IV Spinning reel as being on sale that week for $3.97.
This spinning reel appears to be designed for nylon monofilament line weights of 6 or 8 pounds. The nickel plated lever on the left side of the reel housing is the antireverse. It is pushed down to activate. Designed for right hand casting only, the gear ratio is 3:1, which is somewhat slow compared to most modern freshwater reels sold today.
Reel Design and Materials Used
The Compac Sierra IV spinning reel somewhat resembles the British Hardy Hardex reel in general design and may possibly be copied from it. It is constructed with few parts compared to more modern spinning reels made today and no ball bearings are used.
The next model in the series, the Sierra V has a more conventional reel body profile.
The reel body of the Sierra IV is made of what appears to be a zinc aluminum die cast metal. The drive gear is made of a dark colored extruded plastic, probably nylon while the smaller pinion gear is made of brass.
What is it worth?
As is the case with most post world war II spinning reels, a Sierra Compac IV reel has little collector value. Its value is only as an inexpensive working fishing reel.
Stambaugh-Thompson's Dept Store Display Ad Youngstown Vindicator (Youngstown, Ohio) Mar. 17, 1963 p. D5 <http://news.google.com/newspapers?id=XpA_AAAAIBAJ&sjid=qlUMAAAAIBAJ&dq=compac%20sierra%20reel&pg=5834%2C603765> Accessed (Jun. 14, 2012)
Eckerd Drugs Ad Lakeland Ledger Jun 18, 1975 p. 14A <http://news.google.com/newspapers?id=Sa8wAAAAIBAJ&sjid=1PoDAAAAIBAJ&dq=compac%20spinning%20reel&pg=4236%2C4595394> Accessed (June 14, 2012) [Compac Model FS 860 Metal gears, die cast body Advertised on sale for 4.99 regular 6.99]