I can't make out if it's a die crack or letter between the R and I in AMERICA but it is raised and any information is appreciated. Thanks again
The photos make it hard to tell, but it's also a Zlincoln, which lowers the chance that it's a legitimate die crack. I'm leaning towards damage or plating issues.
Can you blow or rinse the gunk off with warm water? Don't rub. It's hard to tell what's gunk and what isn't.