You can find that whole assembly on eBay for like $75 ish for chrome bell, internal clip and the Pcv valve and lock nut. Mine came from a donor car.
As for the underside- I cannot. My covers are on the head already. Under the cover is a plate with 2 screws. It basically keeps oil from splashing up into the bottom of the valve so it won’t get sucked in and burned. If you want a picture of the underside of the pcv chrome bell- let me know. Plenty of pictures of that on line already.
