heres a 3M product of Butyl tape with blocks, it doesn't state the block size, it'd be good to know what the OE block size was. Even if you couldn't buy blocks & presume you could make some out of hard rubber spacers. I'm guessing they're just stand off blocks for the glass from the window frame, that way the glass can''t slip down & bang into the body & crack.

Anyone know the size of those blocks?

here's the 3M stuff...

http://www.butyltape.org/3m-08612-window-weld-38-x-15-round-ribbon-sealer-kit/