Did Fox stamp the serial number on the buttstock? If so, where?

Yes, at the head of the stock. The stock must be removed to see it.

OK, another question: this particular gun has a hard rubber or bakelite buttplate. What should an original look like? Serial number is in 22,000 range.

I've always been led to believe that XE grade Foxes came standard with leather faced Silver's pads, but I suppose a customer could order a hard rubber butt plate of any style he wanted. Galazan thought this style is what a Fox customer may have chosen.
https://connecticutshotgun.com/product/a-h-fox-butt-plate/

I had two 20s and both came with Silvers pads. Bobby

In this case the customer asked for the gun to be just like his Holland. I guess that's why it ended up with a straight grip and hard butt.

That CSMC plate is sort of like the early style butt plate, as used on the 1910 vintage gun on the left here --



By the time the XE-Grade came along the butt plate A.H. Fox Gun Co. was using had the ring around the screw hole like the other four. The butt plate with the rings was used to the end of Savage production. Generally speaking the butt plate screws would be engraved a bit on C- and higher grade guns, but that is kind of hit or miss.

While a leather faced Silvers recoil pad and Lyman twin ivory sights were "standard" on the XE-Grade we have seen production cards calling for other recoil pads, a butt plate, plain checkered wood and the skeleton steel butt treatment. Likewise we've seen cards where the customer wanted just the front ivory sight, just a metal bead front sight, or the Marble's Bi-Color front sight.

Well, I had my friend look and the buttplate is horn. It is curved to match the curvature of the stock. Do you think it is original?

I would imagine that it looks original to a lot of people, but that has no bearing on it. What does the factory letter say?

Order a letter from Savage Arms or join the Fox Board and order the card for the gun, (which may or may not state the what was on the butt end of the stock)!

The work card says nothing about it. But there is the notation "rest of gun just like his Holland gun" and "make light as possible".

Does the current LOP match the the finished LOP listed on the factory card?

If it was shipped with a silvers pad and then the owner removed it and put a buttplate on the gun, I would expect the current LOP to be shorter than that indicated on the card.

The LOP is 14 5/8", same as work card.

I have reviewed all of the factory cards for XE's in the 22xxx range. I am keeping a tally of all the XE's in this serial number range. If the gun was originally fitted with a silvers recoil pad it was recorded on the card in my opinion.

It's not there, Craig. And since the work card asks for it to be built as close as possible to his Holland I'm pretty sure the horn is original to the gun.

If the gun your referring to is 22658 then it was not fitted with a recoil pad as shipped in my opinion. E-mail me pictures for my files. Craig