Yes I have seen those posts.....really seems like it would not do much as that foam would smash pretty quick, and it is really not that tough of stuff, I think it would get uneven.
It is cheap enough to try, and seems like if it does not work just pull it out....no harm done.
I do know glass bedding works on powder rifles, and that is a bit of a process.
Really what I think is getting everything as close to the same shot after shot, There seems to be more of these posts popping up with more and more people getting into air gunning. People get a PCP then go to a spring rifle, and they have trouble. It usually starts with bad mouthing a specific brand, usually Gamo, as they are sold at wally world. They return it, buy an R7 sometimes they will put the time in, most of the time they think well I got a "good" gun now and I still can't hit the planet Earth with the muzzle pointed straight down. Then these questions come up.
I have said this many many times, MOST spring guns are hard to shoot, magnum springers are very hard to shoot well, lower power guns 500-ish fps, or really heavy monsters are more forgiving....get a heavy low powered gun and it generally shoots real well.
I have one of those Egypt trainers looks a little like a Hakim in 22, under lever from the 50's and that thing has to weigh 10lbs. Shoots very well.
Also have a few Gamo's some pretty old, others new and very high powered guns that are very light, got gifted to me because they would not shoot straight....they do shoot well it just takes lots of practice....and testing.