Value will very much be determined by how the repair goes, as so many things are mismatched the overall value is not what it could be. I think you said the trigger guard assembly, bands, bolt are all mismatched parts, not even correct (98b) parts.
While any 98b is a tough rifle to find, the dated ones are worth more, this range is less common than the e-f blocks but still there is no premium for that generally. This would be a project rifle for anyone buying, and 98b parts are hard to find and expensive usually. I would say the value as it is now is about $600 or so, restored well it could double if you find some 98b parts and fix the stock in a professional way.
There is no firm answer for this, 98b's do not show up regularly on Gun Broker or for sale, a matching stock is very helpful, but unless the rifle is problem free value questions get squishy because there are so many variables, not the least of which is finding someone who wants another project rifle. Most collectors have several...