Help identify 12” spigot internals replacement
I would be very surprised if anyone could identify the make and model of this and if they could, you probably wouldn't be able to find just the internal parts. At the end of the pipe your piece slides in a valve seat which could be bad.

This type of spigot or sillcock is about 12" long and is sold as a complete assembly. The handle at the front turns the shaft inside the pipe which, in turn,  opens the valve at the end. The end, which is indoors, is where you tighten or loosen the entire fixture to your water pipe. Hope this helps. See below for an example: