Hi Rdj, Congrats on the Hepburn. Asking the value of one is like asking how high is up. It sounds like the one you have is in mint condition, so that helps the value. At gun shows, I haven't seen one less than $1000, and very few at that. There again, depending on what style, condition, and the buyer's enthusiasm, the sky is the limit. At auctions, they tend to sell for more than my humble opinion thinks they are worth. Example - a recent rebarrelled, reblued 45-70 auctioned locally at $4500(+20% buyers premium and shipping) I thought is was (IMHO) an ugly specimen worth about 1500. Had a friend offer me a pristine original 25 caliber for $4200 and I am still kicking myself for not buying it.
Now that Tom Rowe's Hepburn book is out, I think the interest will grow and that will make them more valuable.
I realize that I said a lot without telling you much. Pictures would help. You can look on Gunbroker and see what they actually SELL for, not the asking prices. You need to create an account for that. And looking at past auction prices realized for Hepburns sold at auction houses can give you ideas.
Good luck,
oughtsix