Long point lugs, chrome socks & fork crown, mid-fork rack mounts. Looks like it once had Suntour Symetric shifters, so I'm assuming 83-85. No manufacturer decals or tubing stickers. Anyone recognize it? I've included a photo of the serial #. Many thanks!

You can go to the Asian Serial Number Guide sticky at the top of the page and figure out the maker.

Asian Serial Number Guide

Any markings on the dropouts and fork ends? It's a Campy derailleur tab, but I'm curious if they're branded Campy, Suntour, Shimano, etc.

Based on the serial number and apparent era, my leading candidate would be a 1985 Maruishi product, though it could be something contract built for one of their clients, such as Nashbar, as I don't recall the Tourace variants having the extensive chrome during this era. The top mount shift levers remained popular for grand touring models, as you didn't have to reach down quite as far, which was a big advantage with a fully loaded bicycle.

I went back and checked my 1985 Nashbar literature. With the exception of the chrome plated blade and stay ends, it's a very good match for the Nashbar Toure MT. Detail photos show what appear to be the same dropouts, stay caps, lugeset, fork crown and Tange Levin MTB headset. Like the OP's bicycle, it also used a top mount shift lever boss. lo-rider fork mounts and rack bosses on the inside of the seat stays. While not a prefect match, the similarities, in conjunction with the serial number format, support it being a Maruishi product.