We don't offer evaluations on this forum. Best bet is to check eBay for Sold
Items to get some idea of what a similar watch in similar condition sold for,
and compare it to the estimate you get for refurbishment. Chances are, the
cost of refurbishing the watch will exceed what it would sell for. Plus, there
are buyers who prefer to have their own sources perform service on the watch.
You may consider selling the watch as-is.
This forum has members who might suggest keeping the watch for sentimental
reasons, and having it serviced. But it appears by your question about market
value and investment, that the watch doesn't mean to you what it might mean to
an
admirer of IWC. In case you wonder, we do not have a sales section on the
forum so you might consider eBay or Chrono24 for sales opportunities.
Good luck however you decide to proceed.