Our '88 factory teak has/had the factory oil finish. (Note that some EY boats do have the optional factory varnish upgrade on the interior.)
Having stripped and varnished most of our interior teak, it appears that the builder used a light cherry stain to "blend" the various colors of veneer and solid trim together. Evidently this was considered a better look for their customers at that time. This darkens it, though, and we have long believed that a lighter look is better... purely subjective...
We much prefer a more natural "golden" look... if you look at the pix in my blog of our interior re-finishing, you can see some areas pre- and post-op.
Perhaps some of the owners with wood finishing expertise can ID the actual oil stain, if you want it tone original. Remember that your old finish will have changed - probably lightened - due to to light over the years, too. Further, if it has accumulated dirt in the oiled surface, it will be darker.
Oh well, if yacht ownership were simple/easy, they'd let *anyone* own one!
Loren
ps: edit: add link with a picture of one of our doors, showing the varnished door beside the bulkhead with its original dingy oil surface. That bulkhead was later refinished.
http://www.ericsonyachts.org/infoexchange/entry.php?100-Vent-Method-for-Cabin-Doors