I understand that the Tracker and Viscount are essentially the same rifle, except that the Viscount has a longer barrel and is rarer. So why chop it and turn it into a Tracker? By putting it into a walnut stock you have as good as got a Viscount Deluxe, and they're even rarer than the basic model!
A bit like the chap who made counterfeit old-style 10p pieces by filing down the 7 sided coins...
Keep as is, I say! And if you want a Tracker, one will turn up.