Your 9th photo down is where you need to look for the dent in the wood. I can't tell for sure from the photo but it looks like a dent might be there. This is where the mono-pod rested when folded up to the stock. There are also sometimes rub marks at the location shown in photo 10.

A staked screw is one that has been peened where it touches the surrounding metal. It was usually done on two opposite sides and it is to prevent the screw from being easily removed. As one screw appears to be mis-shaped by a screwdriver, it is unlikely to still be staked.

You do have the monopod band but that doesn't mean it originally had one. They used up the bands that were in inventory before moving to the non-monopod bands.

If someone can identify the series, that should tell us whether it was supposed to have one or not or at least if it was a transitional piece which may or may not have had one.

I stopped guessing on the series because I can't tell one from the other easily and they rarely look like the images in the books. Neither of yours resembles anything that I can tell which just means it may be lightly or double struck.

The Type 38 should have a dust cover. Of that I'm pretty sure. The 99 may not have been issued with one, depends on the series.