Red 1680 Sub Questions

[dribelin]

I have a couple of questions concerning what I believe is a 1680 red submariner. My dad bought the watch new in 1970 and wore it pretty constantly until about 5 years ago. The last service on the watch was years before that and I'm trying to figure out now who serviced it last. The issue is this... After removing the band, which has been replaced per his recollection, i encountered the 1680 designation between the top lugs and serial number beginning with 2631 which I'm finding dates the watch to either 1969 or 1970 which should have the red Submariner lettering. The dial has clearly been replaced by a 16800 dial which is in very good condition. The hands appear to be original and have an aged "patina" I see referred to here. Also, they don't light up that well but the hour marks on the dial light up green. Are there any steps I can take to put this watch back in its original condition or is it already too much changed to justify buying an original dial for it? The watch runs but does need service I'm sure. Any advice would be greatly appreciated. Also, I can post pictures if it would be helpful.

Many thanks.