Yes, the gun is probably worth more than $850 if it's in the shape as you described. As s&wchad states, the difference is mostly that the saddle ring and stud were not installed on these eastern carbines. And yes, there were a lot of options that Winchesters offered. Anything that was a factory option will increase the value of the rifle.
These Winchester Lever Carbines are great handling little rifles, I have a first year 30WCF SRC that I wouldn't take anything for.