The Kobold flash was used for Han's droid caller in ROTJ(the Linoff flash was used in ANH & ESB), but it looks like you don't have the correct model.
Please explain what leads you to THAT opinion.
The correct flashes are 5 inches long (minus the reflector and that insert of course).
Here's a pic of my original Kobold, for comparison. My understanding is that this is the Han version from ANH.