Hello, and welcome. Although I don't that exact model, I do have two of the older versions of I believe the same rod- the FF85 which is likely very similar. They are not my favorite rods, but, they work very well as an all around rod, it's just that personally I prefer 7.5'-8.0' over the 8.5' or longer rods.
You can read this for information of the progression of Fenwick through the years and some descriptions of various models-
https://wiki.fiberglassflyrodders.com/wiki/FenwickAnd a quick site search turned up several hundred pages mentioning FF857 Fenwicks, a few that might be relevant;
viewtopic.php?f=3&t=57911viewtopic.php?f=2&t=59283viewtopic.php?f=2&t=60765viewtopic.php?f=3&t=8571viewtopic.php?f=2&t=10907viewtopic.php?f=2&t=45974Value of these rods is in the fishing of them as rule, it seems they made and sold lots of them during ~20 year run and that is reflected in the resale market, not limiting just to the Woodstream years there will almost always an 8.5' Fenwick for sale on eBay. Average to excellent rods that I have watched sold from ~$50-$125 with the near mint ~$150; I don't watch them all and some may have sold higher, but... to an avid collector for the purpose of collecting there seems to be no limits.