I can only give you my opinion as an owner of one in a previous life, but if you want a firm valuation, try your local Gunshops and see what they offer.
From what I can remember the Finnish Lion is a very basic Match Rifle made in the same factory as Sako and Tikka. The Match Rear sight is of a much simpler construction than that fitted to products from say Anschutz, Walther, or Feinwerkbau, and the finish to metal and wood is not up to the standard of products from these suppliers also. Mine certainly didn't perform so well as a shooter as rifles from the above, all of which I've tried.
Generally I'd say that there are a lot of better quality Match Rifles from the era of the Lion available at bargain prices, and I'd guess that it would sell to someone who wanted to cut it down and screw thread it for use as a single shot Sporter, which is what happened to mine. Pure guess on price at £50 or so, based on what I've seen Anshutz, Wather and Feinwerkbau pass through someone's hands for recently.
HTH, even though pessimistic,
Vic T