Batch OCR (Enhance) on folder - skip files that do not need OCR?

Is it possible to Enhance/recognize text on multiple files in a folder, but skip files that do not require OCR?

The use case here is a folder containing PDFs, any of which may be scans and any of which may have been exported directly (from, e.g., Word) to PDF. (That is, I want to batch process folder with PDFs and OCR only the scans.) 

The scans require conversion to be searchable/selectable but the exported PDFs do not.

Having run a few batches, I note that the Enhance engine processes both scanned and exported PDFs.