Jack,

My opinion would be that it is definitely not an Ithaca forend, I’m starting to question if that gun originally had a beaver tail forend. I’ve never observed a forend that had those milled areas as yours.
Does the forend have the long screw going from the front of the forend that fastens to the forend metal?

Since it is a 5 with silver birds versus gold, is it in the 454,000 serial # range?

Thanks,
Stan

Checkering pattern looks identical to my G2 stock.

All I can say is, if it were mine I'd be shooting Doubles trap with it. Maybe a tad open but if you are quick enough.....

And trap shooters don't care what's been done to it.

Serial range
 

Serial no is 4500xx. Not sure about the screw you asked about .

Jack, like on a Parker btf.

The few NIDs I've been inside of had the serial number stamped in the head of the stock.

It appears that forearm was highly modified to move the Deeley latch quite a ways forward. A Normal No. 5E forearm --

Attachment 114422

The OP's forearm --

Attachment 114423

It appears the base of the forearm iron is an ejector iron with the metal yoke that the screw at the back of the forearm wood goes into.

Attachment 114424

Attachment 114425

A normal extractor forearm --

Attachment 114426

Ithaca Forend
 

Dave brings up some good points, I’m not sure what’s all going on with that forend. I’ve included a few pictures of a Grade 5E forend

I appreciate all of your input. I will be selling this gun for the family of a deceased friend of mine and your information helps me to get a handle on what to ask for it.

Good luck in Louisville this weekend Jack.

Another 5E....