The cache location is here: %LOCALAPPDATA%\Microsoft\Device Metadata\dmrccache you may look for the 2 devices via GUID there.
for instance: C:\Users\%username%\AppData\Local\Microsoft\Device Metadata\dmrccache\en-US\00e644cc-0b1e-4039-80b9-a8fe297d3897\DeviceStage\Device\en-US
is where the icon image is located for my Samsung printer.
Look for the proper GUIDs there for each printer. It's possible that one of them doesn't even have a "DeviceStage" folder, which may help you troubleshoot, since that would mean that the "Device Stage" functionality in Win 7 isn't getting correct info from the device to get the Meta data from MS on which icon set to use, what tasks are available for that specific device (like ordering supplies, contacting their support, etc. on a particular tab)
That should help you some, but you'll need to look at the properties and see if the Manufacturer, Model, Model #, etc. is correct between the two installed. If it isn't, then something on the one that is incorrect isn't setup on the printer itself correctly or on the print server if there is one.
Hope that helps.