More info.
Universal was one of the earlier makers of commercial carbines.
The early rifles were true replicas of the GI carbine, and used all GI parts assembled to a cast steel receiver.
As time went on, the supply of GI parts began to dry up, and Universal began to make more and more parts by casting.
Finally, in the late 70's, Universal did a complete redesign of their carbine, and the result was actually more of a carbine "look-alike".
The new carbine has a very different gas cylinder assembly, a two recoil spring arrangement, and a operating rod made with a cut-out area on the cammng surface which exposed the bolt's locking lug.
Quality of these later carbines fluctuated badly.
When the company folded, it was bought out by Iver Johnson which made a carbine until they too folded.
Strangely, Iver Johnson made their carbines as true replicas of the GI carbine, NOT like the highly modified late model Universal's.
What you have depends entirely on whether it's an earlier GI-type or a late modified type, AND on how your particular carbine shoots.
Like most gun companies, Universal never released any serial number info, and there is no one known who can give you a definite production date.
Value depends on the type Universal, the actual condition, how well it works, and where and who is buying it.
In other words, it's worth just what someone is willing to spend on it.
For a better idea, check a recent copy of one of the gun value books like the Blue Book, or check prices on the online gun sales sites.