The crazy thing is, most ham that's perfectly shaped isn't using any kind of meat glue or enzyme (it's basically only used on expensive cuts of meat), but just pressed together in that shape and naturally re-adheres during cooking.

"So essentially all boneless hams -- which are restructured products that consist of meat pieces bound together -- don't include meat glue, but rather salt-soluble protein as a binding agent that is extracted from the meat surface during a process called massaging, or tumbling."

https://www.psu.edu/news/agricultural-sciences/story/meat-glue-issue-involves-wide-misunderstanding-expert-contends