Former fourplex, now a duplex. Potential issues converting back?

[Kit Cross]

I am looking at a multi unit property which obviously used to be four unit property but has since been (somewhat badly) converted into a duplex. I can see where the wall inside has been removed, and each of the two units now has two front doors (!), two bathrooms and what would have been the kitchen has been made into an extra bedroom.

The reason for the conversion is unclear and the agent doesn't have any info on when it was done. The zoning code for the property is R-2. If I went ahead with this, I would want to convert it back into a fourplex. Aside from getting new electricity meters, are there any reasons why this should be problematic with the zoning code?

Thanks for your time.