The gun was originally made in .30-06 and later chambered for higher pressure rounds, which tended to tear up the insides a bit on some guns. A lot of guys swear by them, and others swear at them. You can expect to get $250-300 for a good one, in my experience. Most guys who have a good one like theirs well enough that there is really no incentive to sell, unless you need the $200-300 you may get. Some guys do like the 742 a little better because it's a carbine.
These were replaced by the 7400 series which have a better reputation even with high pressure cartridges and therefore can command a little more money, but none of the stock guns is rare to my knowledge.
The Second Amendment does not exist
to protect the gun rights you like.
It exists to protect the gun rights you hate.