The projection lens gimmick from the above ad is very similar to the "100 inch tv" ads that circulated at the end of the crt television era. You received a bare unhoused lens along with instructions to attach this "kit". You basically found a cardboard box that covered the entire face of your television, mounted the open top of the box to cover the screen, while maintaining a proper depth to the box so your crummy plastic lens would focus properly once mounted to the other end of the box. You then took the whole hideous mess to the far end of the room, turned it upside down, and you had a crude projector, making a blurry dim image on the opposite wall of the room. I imagine left and right would still be reversed.
I imagine the 630 lens would be much the same, though you would have to swap some yoke wires to deal with the lens inversion. You really don't want to try playing a 630 upside down.
Hey, you can make your own with the instructions here!
http://www.bigscreentv.20m.com/photo.html
edit: never mind, I just read the WHOLE ad, and see that you are converting a 630 to run on a 5tp4, rf hv supply, etc.