I'm looking for some recommendations from the experts as to what instructions I should give to Sinn when I send my watch in for servicing. I have a late 90s/early 2000 version of the EZM2 that features the original tritium illumination. It's my understanding that these early 3H variants are somewhat sought after by Sinn enthusiasts at the present time. I'm overdue to send it back to Frankfurt for another battery change and oil fill. It's last servicing was probably around '04, before Sinn made the change over to the newer lume friendly grade of silicon oil. The discoloration on the indices from the older more corrosive style oil is starting to become readily apparent. I've read that Sinn is inclined to replace the dials at servicing when they encounter this discoloration, but that if you request, you can have the original dial left in place.
So what's the best play here? Would the watch retain greater value if I left the discolored dial intact, or is the difference in value so negligible that it doesn't matter? Or is it possible that they could touch up the indices on my original dial and make the indices appear whiter? Any comments, ideas or suggestions?