Never heard of a recall.
The Tech Tip was calling out that some early blocks had those caps but I personally have never seen any, and I have never seen a Hemi break a cap either., at least a normally aspirated one.
I dug that book out my revision is 1976. I do not know who wrote any thing in this book because both the front and back covers are half torn off. The book is just a book to read. The book is basically what was done back in 1972-3-4. Time really has passed this book behind. There are a lot of things that are not true also. Here is an example of this I do not like, if you are going to race a Hemi I would toss the stock connecting rods away and buy after market. Next take all the valves and toss those beside the rods. You want to lighten everything that moves in a Hemi. This is just a start with this book it is a good History lesson but not all things are correct. I always wondered why my 2017 Chevy truck takes more oil in its oil pan than a stock Hemi Oil pan does. These Hemis with a stock oil pump can suck the stock pan dry and what happens booooooom out the side of the block thank Chrysler for not putting a bigger pan on these hemi, but I did 10 Quarts. I use an accumulator that if the pressure drops past a certain pressure it pumps quarts of oil from the can into the motor hopefully solving the problem till I can get it stopped. There are plenty on moparts that know and have raced Hemis and these are the guys you need to talk to. Some raced in the parts and other raced in the past and still do. The 1965 also had a blower on it and never heard anything like a main cap. Not huge HP for the day but still a lot of power. I would like to see one of those caps or at least a picture of one. Makes you wonder how many rolled out this way, and yes another posted is correct, Chrysler trying to save a penny on your hard earned money when you buy a car.
Larry Shepard from Direct Connection collected the info from all the engineers and complied the Tech Tips and eventually the “Bible”.
He made publishing errors like every one else - some were corrected and some not.
As for the caps, one would wonder if the first Hemis had good caps, then in an effort to reduce expense it was decided to use cheaper material or maybe a change in casting tooling was made then eventually corrected.
No way would a plain cast iron cap live in NASCAR racing.
