It is possible to use the SmugMug publish service plug in to sync galleries to LR desktop. It’s safest to do it one galley at a time and the on-line photos will be matched to the original in the Lightroom catalog where available.
Go to Publish Services and select a collection for a SmugMug gallery with zero images. Right-click on the gallery name and choose “Edit Gallery” and then put a check mark in the box “Sync Photos” and click the Edit button. A progress bar will start and the collection will be populated automatically where there is an exact file match.
During the process you may need to take action on individual photo suggestions e.g. to accept or reject the suggested match for any images displayed in the left and right panes where there may be more than one match e.g. raw & jpeg, tiff, PSD or different sizes with the same file name. For example if there are two possible matches the right pane will display two tabs at the top. It’s then a simple button press to accept the best match or dismiss in order to find it manually. Click image below to enlarge.
Not intuative, like many thinks in LR but effective. Thank you for the help, 99jon.