After 20 years in Missouri, I've relocated back to the Quad City area to be closer to family. I know I have to get an Iowa drivers license before submitting my CCW paperwork, but will I need to take a training class or will my existing Missouri CCW permit get me a pass?

Since no else has answered I'll give you some help. Iowa Code 724 is the main weapons code. It is not by far the only code governing weapons and their use in Iowa. But 724.9 gives the training requirements. I do recommend some quality training from one of the instructors on this forum. There are a great many instructors, and I use the term loosely, that do not fully understand the law and tell people the wrong things regarding the actual law. I pulled this link off the IFC site so I hope it is the most recent and includes any changes. IFC (Iowa Firearms Coalition) is a good place to get answers as well as here. Here might be better b/c the IFC facebook page has a lot of folks who are not up on things answering posts mixing facts with misinformation.

https://www.legis.iowa.gov/docs/code/724.pdf

Welcome back to the area. I live northeast of there, it work in the cities.

Can't help on your question though. Iowa's licensing requirements are pretty easy to meet wether your current stuff does or not, so don't worry too much. Worst case, you're out a couple bucks for a couple hour training and you're done.