You were right on! When I turned on the ignition switch without starting, the 4th light down came on indicating oil pressure. Your solution was confirmed by my son, a marine engineering commisioned officer in the U.S. Coast Guard. Thanks for the help! It's nice to know that answers are available from knowledgeable club members!
For others' information, the sequence on this panel is now known to be "Low Coolant, H. Turbo BS, Coolant Temp, Oil Press, Trans Temp." Hope this will assist someone else in the future.
Thanks, "My My Hey Hey"! i turned on the starter switch and on came the 4th light down, indicating it's the "oil pressure" lamp, making the other opening the "H Turbo BS" lamp by default. My son the USGC Marine Engineer confirmed your troubleshoot and suggested the same path. Nice to have helpful folks like you on the site. Thanks again!