Sorry, I was replying about different URLs, you're focused on the caching question. Yes, most browsers would retrieve again. That's the price you pay for having the same file be able to be viewed or able to force a download.

As a VDN (video delivery network) we're focused on 100MB - 8GB video files, so our clients' primary goal is to avoid ever having the file attempt to display in the browser unless as a media URL purposely supplied to an embedded player. In general a raw video file URL would be for a download, and forcing Content Disposition saves having to explain the "Right-click, Save As..." dance regardless of browser.