Your best bet for an appraisal is looking at ebay "sold" postings. not just completed, but ones that actually sold.

You have the tube and sock, and the FF855 is a nice and uncommon rod, so some where between $110 and $220, probably somewhere around $150 would move reasonably quickly, but like anything, you have to find the right buyer. It has a lot of things going for it (5wt, cork reelseat, but the etching takes it out of being a true collectors piece.

I've seen them go for lower, but not when they are in good condition and advertised correctly. It's a great rod, but there are a lot of great 8' 6" 5wts out there these days and unless you are into vintage glass (like those of us here). Most people have a rod that fits this niche.

I’d think the presence of a slide-band seat would make it a little more desirable. Cool rod, uncommon on the secondary market.