Lakewood blowproof block plates 15765 & 15781

Will these fit any Lakewood bells? Or do they have to be a certain year/model. Example any small block will work with this small plate?
I know the small block block plate fits the later Lakewood bellhousings before they were discontinued, the part # 15781 still shows up on multiple websites but will frequently show out of stock because these went obsolete several years ago when the Quicktime bellhousings came out, thanks Dave.